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Manifest
Script Kiddie Asshole
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Would someone like to try this? Graphene Production
http://cen.acs.org/articles/92/web/2014/04/Solution-Graphene-Production.html
Graphene is easy to acquire, at least in small amounts. The first scientists to isolate the strong, two-dimensional carbon material simply pressed a
piece of Scotch tape to a chunk of graphite and peeled it off. But mass production of graphene for commercial uses remains a challenge. Now,
scientists have shown they can rapidly produce large quantities of graphene using a bath of inorganic salts and an electric current (J. Am. Chem. Soc.
2014, DOI: 10.1021/ja5017156).
Several other methods have been developed for producing graphene, but each has its drawbacks. Growing the carbon sheets takes too long, and chemical
vapor deposition requires a metal catalyst, with a second step to remove the metal. Other methods using solvents or surfactants can harm the
electronic properties of graphene or produce lower yields.
Xinliang Feng and Klaus Müllen of the Max Planck Institute for Polymer Research, in Mainz, Germany, and their colleagues decided to improve upon an
electrochemical technique for producing graphene. Instead of using acids, which oxidize the graphene and reduce its conductivity, the researchers
prepared solutions of various salts, including ammonium sulfate, potassium sulfate, and sodium sulfate. Into their mixtures they placed two
electrodes, one made of platinum and the other of graphite, which is essentially a conglomeration of many layers of graphene. When they ran 10 V of
direct current through the graphite electrode, it began to shed layers into the solution, a process called exfoliation. They kept the current running
for three to five minutes, separated the exfoliated flakes from the solution, and washed away excess salt with water.
The process turned more than 75% of the graphite electrode into graphene flakes. Approximately 85% of the flakes consisted of one to three layers of
graphene—the most desirable electrical properties come from single and double layers of graphene.
Of the solutions they tested, the ammonium sulfate worked the best, producing the highest quality graphene in the fastest time. In one test, the
researchers were able to produce approximately 16.3 g of graphene in 30 minutes. But Feng sees the potential to scale up production to the kilogram
scale needed for industrial use.
James M. Tour, a synthetic organic chemist at Rice University, calls the work “very nice—not the first time such electrochemical exfoliation has
been done, but the authors here get it to work more efficiently.”
The exfoliation process is also more environmentally friendly than previous methods for generating graphene, Feng says, and doesn’t require high
temperatures. He plans to test other electrolytes as well as different forms of graphite in an effort to scale up the process. The individual sheets
of graphene, however, are still very small, at most a few millimeters across. Producing sheets on the centimeter scale, to build something like a
transparent electrode, remains difficult, Feng says.
To demonstrate a use of their graphene, the team mixed the powder they produced into N,N’-dimethylformamide to produce a graphene ink, which they
painted in a thin film on a piece of paper. They used two pieces of treated paper to make a supercapacitor, showing the material’s potential use in
flexible electronics.
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WGTR
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Wow. Thanks for posting that (both you and Morgan). I'll definitely be trying it, but probably not right away. I have a
few things on my plate already.
I need to read through the article in a quiet moment (don't forget the supplementary article too). The main thing is that
the surface area needs to be very high, and it needs to stay that way once deposited on a substrate. I'll look into it when I
get the chance.
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IrC
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Chemistry is not my area of study but I do dabble somewhat with what I know. So hopefully this question is not too dumb to ask since making Graphene
really interests me. I cannot afford Platinum electrodes. If I used ammonium sulfate with graphite for one electrode, would it work to use Titanium or
Tungsten for the other electrode. Or is there some undesired chemical reaction going to take place? Or would it not work at all without Platinum?
"Science is the belief in the ignorance of the experts" Richard Feynman
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Baffled
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Please, if you try any of this yourself, do so in a fume-hood. Graphene might be a lot less benign than previously assumed:
http://news.brown.edu/pressreleases/2013/07/graphene
Small scale human testing has already begun, given the absence of any "don't try this at home, you might get cancer" warning: http://www.scientificamerican.com/slideshow/diy-graphene-how...
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Mildronate
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How do you will know that is graphene? YOu need SEM then.
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forgottenpassword
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I have made graphene with sellotape and a graphite pencil. It is a useless product!
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HgDinis25
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Baffled, I think that calling Graphene a potential carcinogenic is way out of line. C'mon we all use pencils. Pencils are made of Graphite and simply
painting your skin with it will make tiny quantities of Graphene. So, let's brand pencils as non benign objects?
I would find it quite disturbing that the odds of Graphene going through cell membranes and entering the nucleus were to be that high, like described
in the articles.
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quantumchromodynamics
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one atom thick
what can the home scientist do with one atom thick carbon sheets?
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IrC
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Useless to whom? Productive posts please. I have a big square that floats in air above 4 NdFeB magnets. Not useless to me it is cool to see it
levitating. I wish to experiment using Graphene to create negative resistance relaxation oscillation. My question is will Titanium or Tungsten work
for an electrode.
"Science is the belief in the ignorance of the experts" Richard Feynman
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HgDinis25
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Being able to produce onte atom thick carbon sheets should alone be rewarding enough.
On top of my head, I remember the awsome Graphene Supercapacitators. Look around the internet and you'll find plenty of information about them.
http://www.technologyreview.com/view/521651/graphene-superca...
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froot
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I'm sure you can use a carbon electrode, Pt was used to ensure no other chemistry complicated the results. Worst case scenario you'd need to replace
your solution more frequently. For one graphene would be useful in photovoltaics as a flexible transparent conductor.
We salute the improvement of the human genome by honoring those who remove themselves from it.
Of necessity, this honor is generally bestowed posthumously. - www.darwinawards.com |
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forgottenpassword
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How big is your big square?
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aga
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Does anyone know how the chemistry of the Edges of a graphene sheet work ?
Specifically, if you made, say, two 1mm sheets, could you combine them into 1 sheet ?
Making a 1mm squared sheet would not be too useful.
[Edited on 20-4-2014 by aga]
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IrC
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Around 25 mm square. Unsure how thin and too fragile to find out without risking it. Pretty thin. Supports the weight of a fly landing on it without
touching the magnets. In fact it has a surprisingly large force holding it up. Surely you have seen one of these they are a common toy among geeks.
The point being in answer to the "what good is it" question I do not own any other substance that will defy gravity by virtue of its diamagnetism with
this much force. Have tried with Bi but Graphene has the highest level I have ever encountered. Along the lines of a frog floating in a
superconducting magnet strong.
http://www.youtube.com/watch?v=xoj_fVVZuxc
My sheet looks very similar to the video except I use 4 1.25 inch square by 3/4 inch thick N48 magnets. You can carefully direct a stream of air to
make it spin incredibly fast. Not too long ago scientists showed it was the fastest spinning thing (material object) we know.
http://www.newscientist.com/article/dn19514-levitating-graph...
I thought every geek had a toy made from Levitating Pyrolytic Graphene?
http://www.ebay.com/itm/Pyrolytic-Graphite-1x1-cm-piece-neod...
Get your geek toy here $6.95 free shipping. Then whenever anyone asks what good is it explain the endless hours of amusement you derive from your toy.
I like the words this seller put on his page since it is hard to find cheap sources of large sheets.
"I can provide bigger pieces (like, 20x20 mm or even 100x100 mm) for the price of 6$ per square cm (massive discounts for larger pieces are possible)
or combine several items if you need. I can also cut any form of any size up to 200x300 mm for the same price of 6$."
After reading this auction page I am talked into getting some N52 magnets to raise the square a little higher while it supports even more weight. Of
course at the time I acquired this toy not even N50 was available from my usual hacker supply sources.
At least not as boring as watching pitch drop. This guy watched for 50 years only to pass away a year before it dropped:
http://www.newscientist.com/article/dn25441-longest-experime...
Hard to believe no one here has tried this:
http://www.newscientist.com/article/dn25442-make-graphene-in...
[Edited on 4-20-2014 by IrC]
"Science is the belief in the ignorance of the experts" Richard Feynman
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WGTR
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Graphene is merely the future of energy storage. It's absolutely useless. I have no idea why anyone would be interested in it. 
Pristine graphene is hydrophobic, and does not disperse into 100% water. It also permanently restacks into graphite sheets if you allow it to settle
out.
The particular flavor of graphene that is usually encountered is its partially oxidized form, graphene oxide. Depending on how it was oxidized,
there are different carbon/oxygen ratios, and different functional groups that are attached to the graphene sheets. Generally, single and few
layered graphene oxide disperses well into water, provided that the pH is neutral and the extraneous salts have been washed out. The thicker pieces
precipitate out of solution upon centrifugation, giving a means of separating the exfoliated sheets from the non-exfoliated ones.
What the article is describing, at first glance, is a process of oxidation and exfoliation by which minimal oxygen is introduced into the graphene.
In fact, it gives the highest C/O ratios of any process that they compared to. Also, manganese is not introduced, producing less hazardous waste as
compared to the typical oxidative processes. This also requires less washing of the graphene afterwards, giving a purer and more suitable product
for electrochemical studies. Strong acids and oxidizers are not used, eliminating the risk of explosions from overheating (Mn2O7 is unstable, etc).
(NH4)2SO4 is fertilizer. So they have essentially reported an easy and non-toxic way of synthesizing low-oxygen graphene.
An important application of graphene is the preparation of high surface area electrodes for supercapacitors. If you look at the SEM images of their
product, the sheets of graphene expand out and wrinkle. This wrinkling is good, because it maintains high internal surface area and minimizes the
tendency for the layers to restack. High surface area and conductivity are paramount in a capacitor. This translates directly into high capacity and
low ESR. Their material has a reported density of 50 farads per gram. This is high, but relatively low compared to the theoretical (250F/g,
depending on how you measure it).
The thicker the graphene layers, the less access the electrolyte has to the internal layers of graphene, and the lower the specific capacitance at a
given CV scan rate. This is obvious from figure S17. Also, the expansion and wrinkling of the graphene layers is not optimal, which explains why
the specific capacitance does not approach the theoretical values. In spite of this, their research is still quite invaluable. It certainly got
me excited. Undoubtedly there will be more research that involves getting the most surface area out of this type of process. This is just
the beginning.
I think ammonium sulfate is fairly stable. If the electrolyte were ammonium nitrate, the nitrate ion could get reduced, even all the way to ammonia,
at the cathode. With a copper cathode, and a platinum anode, a nitric acid solution will go decidedly basic as ammonia is produced. In this case,
I think a platinum cathode was used out of habit. Anyway, I have a platinum electrode, so I'll use that just to be sure.
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Chemosynthesis
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Quote: Originally posted by HgDinis25  | | Baffled, I think that calling Graphene a potential carcinogenic is way out of line. C'mon we all use pencils. Pencils are made of Graphite and simply
painting your skin with it will make tiny quantities of Graphene. |
According to some biophysicists I know, that's not the case, and the size/diameter of the graphene produced can be very damaging to cells. Merely
writing with a pencil may not produce the proper angle, diameter, etc. for significant penetration past the epidermis.
Additionally, inhalation may be most dangerous as the lungs are highly vascularized and may afford entry into systemic circulation, which is very
dangerous from a toxicological standpoint.
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Baffled
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Well, at least we can just burn the waste, try doing that with asbestos!
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forgottenpassword
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Good luck with that. It looks like soot to me. http://www.appliedgraphenematerials.com/products/graphene-po...
In fact it is soot! There's one born every minute.
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IrC
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Enough with the useless posts. If you think Graphene is useless why talk about it? Try studying these patents on the subject.
http://www.freepatentsonline.com/result.html?sort=relevance&...
"Science is the belief in the ignorance of the experts" Richard Feynman
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WGTR
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I managed to oxidize some flake graphite using an adaption of the electrochemical method.
I thought I had graphite foil, but it turned out to be some strange paper made from carbon squiggles. It exfoliated in a really weird and useless
way. Instead, I took some Asbury 3061 flake graphite, and bound up a gram into a small cloth pouch. Contact with the graphite flake was made with
a platinum anode. A graphite cathode was used, which did not deteriorate during operation. 0.1M ammonium sulfate was used (straight out of the
20lb bag of fertilizer) as an electrolyte, with no purification. 10V was applied across the cell, and about 0.5A was maintained. After 30 minutes
the graphite flake was washed out of the pouch and into a separate beaker. Some flakes were unchanged, but many of them appeared much darker than
usual. Upon closer inspection under a microscope, these flakes had expanded out like an accordion, like a graphene slinky. Basically, the graphite
changed from flat flakes into expanded columns that were a couple of times taller than their width. It was pretty neat, actually.
After washing this stuff out with a large volume of DI water on filter paper, small amounts were added to DMF and sonicated. After about 10 minutes,
the graphene was mostly exfoliated and dispersed into the DMF solvent, where it has remained stable for at least 8 hours. Much of the graphite was
not oxidized enough, and did not exfoliate, sinking to the bottom of the solution after several hours of settling. The solution itself remained
dark, however. Some parameters need to be adjusted to improve the oxidation.
I'd like to get some of the expanded graphite into the SEM to get some pictures, but it may be a while before I can do this. I have a day job.
There are actually several different forms of carbon. The soot you are describing may contain a mix of amorphous carbon, graphite, graphene, carbon
nanotubes, random tars and other organic junk. Getting the desired form of carbon in suitable purities can be quite difficult. Ask any guy who's
had to shell out big bucks to buy a carbon rock for his girl.
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HgDinis25
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| Quote: Originally posted by Chemosynthesis | | Quote: Originally posted by HgDinis25 | | Baffled, I think that calling Graphene a potential carcinogenic is way out of line. C'mon we all use pencils. Pencils are made of Graphite and simply
painting your skin with it will make tiny quantities of Graphene. |
According to some biophysicists I know, that's not the case, and the size/diameter of the graphene produced can be very damaging to cells. Merely
writing with a pencil may not produce the proper angle, diameter, etc. for significant penetration past the epidermis.
Additionally, inhalation may be most dangerous as the lungs are highly vascularized and may afford entry into systemic circulation, which is very
dangerous from a toxicological standpoint. |
Can you please provide some references? It has caught my atention and I would like to study more about the subject. What about carbon nanotubes? This
might seem insane, but could you stab someone with a huge carbon nanotube without someone even knowing it? (scientific fiction I guess)
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IrC
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| Quote: Originally posted by WGTR | | I thought I had graphite foil, but it turned out to be some strange paper made from carbon squiggles. It exfoliated in a really weird and useless
way. |
Thinking about building a Graphene layer lead me to reading this patent:
Graphene deposition and graphenated substrates (United States Patent 8487296)
Attachment: US8487296B2.pdf (490kB)
This file has been downloaded 501 times
"Science is the belief in the ignorance of the experts" Richard Feynman
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forgottenpassword
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How is it a useless post? Some people may not know that graphene is produced as a soot by the combustion of
ethanol in air. I linked to a website that both describes the process and shows the product from the world's largest supplier of graphene. You linked
to freepatentsonline. Thanks for that!
[Edited on 21-4-2014 by forgottenpassword]
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IrC
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forgottenpassword "I linked to a website that both describes the process and shows the product from the world's largest supplier of graphene. You
linked to freepatentsonline. Thanks for that!"
I provided a link to a search at 'freepatentsonline' for reasons stated below. Also I uploaded what I thought was a useful PDF to this site. Even if I
had so what? Your "Thanks for that!" remark after mentioning your link in a way which implies it is 'more useful' and mine is therefore 'less useful'
is not very productive to the subject at hand. Everyone should be able to feel free to provide information and sources they believe is on topic and
useful without fear of being belittled.
Is studying patents on the subject a waste of time? Is freepatentsonline a useless resource? Is there a point to this hijack adding further useless
discourse on the stated subject?
Title of thread: Would someone like to try this? Graphene Production
Comments not adding useful input to the science behind the subject:
"It is a useless product!"
(Originally posted by WGTR "Graphene is merely the future of energy storage")
Your IMHO 'useless' comment to WGTR as addition to the subject (sans link which is useful):
"Good luck with that."
"It looks like soot to me."
"In fact it is soot!"
"There's one born every minute."
Then there is the additional post I am replying to now which fails to further information on the subject in the thread title. I did not like the
replies I quoted above so I said something about it. Get over it. To actually provide more useful information here is a few more patents:
Attachment: US20070158789A1.pdf (358kB)
This file has been downloaded 463 times
Attachment: US20080176058A1.pdf (1.4MB)
This file has been downloaded 511 times
Attachment: US20090155561A1.pdf (182kB)
This file has been downloaded 476 times
Attachment: US20100035093A1.pdf (342kB)
This file has been downloaded 499 times
Attachment: US7619257B2.pdf (91kB)
This file has been downloaded 481 times
While I may not have the infinite intellect some may require to make posts on this site, it seems clear to me comments such as "It is a useless
product!" and "There's one born every minute." are not very helpful to the OP's reason for this thread. My adding a list of or posting patents was
merely in reply, to show real world uses for the as you say 'useless product'.
"Science is the belief in the ignorance of the experts" Richard Feynman
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Chemosynthesis
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| Quote: Originally posted by HgDinis25 |
Can you please provide some references? It has caught my atention and I would like to study more about the subject. What about carbon nanotubes? This
might seem insane, but could you stab someone with a huge carbon nanotube without someone even knowing it? (scientific fiction I guess)
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References for which part? I could try and ask the biophysicist colleagues, but it seems to make sense to me given that pressure is dependent on
surface area, and lipophilic absorption through various means also relies on surface area and molecular size as well as partition coefficient. I
cited a paper or two on nanotube drag forces. Two excellent examples of that principle in action are through the colon with ingestion and
subcutaneous injection.
Additionally, I can think of two mechanisms by which lung tissue is toxicologically important, both stemming from vascularization. One is access to
systemic circulation of your toxic agent, and the other is easy access of the immune system to the lung. I could look through my shelf at work for
the perfect review paper, but lung cancer (among others, such as breast, etc.) is often associated with inflammation.
It gets a little contentious to make claims here, depending on who is fighting for what grant, unless I start citing lots of data, but inflammation
and wound healing with EMT/MET mechanisms are potentially carcinogenic by epidemiological correlation. Fine metal particles actually always present a
cancer risk, but substances such as asbestos are better known for their apparent efficacy as etiological agents.
One mechanism for this in the lungs involves, presumably, Tumor Necrosis Factor (TNF) cytokines which cascade from cell signalling in mast cells,
which logically have increased access to the lungs or colon due to the high amount vascularization needed for efficient gas exchange and absorption of
food, respectively.
Hopefully these will provide enough of a starting point in mitigating any scepticism, but if it helps, I work in pharmacology with plenty of
background in oncology, which is very toxicological in nature. If you're still dubious, let me know.
http://pubs.acs.org/doi/abs/10.1021/nn102763b
http://experts.umn.edu/pubDetail.asp?n=David+Y+Pui&u_id=...
http://aje.oxfordjournals.org/content/148/3/241.full.pdf
http://ntp.niehs.nih.gov/ntp/roc/twelfth/profiles/cobalttung...
http://oes.tamu.edu/guidelines/Nanotechnology/Inhalation_Tox...
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2783215/
http://www.particleandfibretoxicology.com/content/11/1/3
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2367012/pdf/MI-0...
http://www.safenano.org/Portals/3/SN_Content/Documents/FEATU...
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1994795/
Edit- and yes, with a needle that thin, you could theoretically avoid hitting any neural pain fibers. Coat the exterior with a local anesthetic,
perhaps an ester for rapidity of metabolism, and it's theoretically plausible the injectee wouldn't feel a thing.
It's also important to remember that cell membranes are not uniformly comprised, and show variation due to gene expression between tissue types. This
could be presumed to affect the energy of penetration, and may make certain tissues more susceptible to damage. The dead epidermal layer, by
contrast, requires no nutrients to its dead husk, and may act as a sponge or shield, which isn't uncommon (hence some agents requiring skin
penetrating solvents, or not being contact risks).
[Edited on 21-4-2014 by Chemosynthesis]
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