<whitequark>
also, solubility of gasses in liquids does not, in general, decrease with t°! I've been lied to my entire life. J. Chem. Ed. 1955, 32(8), 399; http://i.imgur.com/2fdxZEg.png
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<DocScrutinizer05>
wow
<DocScrutinizer05>
my world collapses
<whitequark>
not sure if sarcasm :)
<DocScrutinizer05>
no kidding, just a tad of exaggeration
<DocScrutinizer05>
I'm actually amaced how much I seem to have tickled your curiosity
<DocScrutinizer05>
sure, it's pretty clear that in the end everything is about energy and entropy
<whitequark>
DocScrutinizer05: I tend to get sidetracked on fundamental-y things. The whole reading encyclopedias from cover to cover thing :)
<DocScrutinizer05>
hehe
<whitequark>
I think I started seriously reading up on LLVM not because I had a language to implement, but simply because I was fascinated by it so much.
<whitequark>
etc.
<DocScrutinizer05>
on a loosely related topic I find intriguing: all about boiling delay, hypothermic liquids and the question why sodawater bubbles come up on a ricecorn you throw in the glass
<whitequark>
hypothermic liquids? you mean supercritical?
<DocScrutinizer05>
probably
<DocScrutinizer05>
like handwarmers
<whitequark>
uh, no, probably not
<DocScrutinizer05>
the stuff with the liquid salts at room temperature
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<whitequark>
got it. I'll remember the right term in a moment
<DocScrutinizer05>
that all of a sudden crystallize when you bend that clickdisk
<DocScrutinizer05>
in german it's "unterkuehlte schmelze"
<whitequark>
it's "supercooled liquid" in english
<whitequark>
aka "undercooled" but I think "supercooled" is more common
<DocScrutinizer05>
just glass doesn't tend to spontaneously crystallize
<DocScrutinizer05>
only very very slowly
<whitequark>
I don't think glass crystallizes at all?
<DocScrutinizer05>
also glass flows, but very very slowly, so it's actually liquid
<whitequark>
glass doesn't flow, it's a common misconception :p
<DocScrutinizer05>
yes, it does, after hundreds or thousands of years
<whitequark>
(glass crystallization) glass, by *definition*, is a solid which is not crystallized
<whitequark>
DocScrutinizer05: source?
<DocScrutinizer05>
common kowledge about e.g. windows in churches
<DocScrutinizer05>
and glass defects getting worse in very old drinking glasses
<DocScrutinizer05>
might be another lie they told me
<whitequark>
it's an artifact of the manufacturing process which has been used back then. you'd blow a bubble of glass and then flatten it. naturally, an edge would be more thick. they were then customarily placed with the thick edge pointing down.
<whitequark>
a very common misconception indeed
<whitequark>
never heard about glass defects though
<DocScrutinizer05>
I heard it starts crystallizing just like that pocket warmer salts, just in ultra slow motion
<whitequark>
I think the very composition of glass prevents it from crystallization
<DocScrutinizer05>
possibly correct for contemporary glass
<whitequark>
lemme find you some sources
<DocScrutinizer05>
anyway the term "unterkuhlte schmelze" I heard first time in relation to glass
<whitequark>
DocScrutinizer05: ok, "Do Cathedral Glasses Flow?", Am. J. Phys. v66, pp 392—396, May 1998
<whitequark>
orrr Plumb, R. C. (1989) Antique windowpanes and the flow of supercooled liquids. Journal of Chemical Education, 66(12): 994-996.
<whitequark>
it mentions two phenomena (zero-creep and anelasticity) which resemble viscous flow in glasses but are not identical to it
<whitequark>
highly fascinating read
<whitequark>
also, it has an amazing description of the ancient glass-making process
<DocScrutinizer05>
sorry, getting late here
<whitequark>
sure, take a look when it's convenient
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<DocScrutinizer05>
cation diffusion, incredible
* DocScrutinizer05
considers glass like a sponge from now on ;-D
<whitequark>
ooooh yes, cation diffusion allows for a very neat trick
<whitequark>
take a thin glass "wire", so thin you could bend it more or less freely, and make it in a spiral, then let it sit for a few days
<whitequark>
you could then just play with this glass spiral, it'll remain more or less in the same shape
<whitequark>
but if you place it on top of liquid Hg, it'll begin to rapidly regain its original shape
<whitequark>
can't seem to find anything on youtube
<DocScrutinizer05>
hmm, cation diffusion should be susceptible to electric current, no?
<whitequark>
hmmm
<DocScrutinizer05>
sort of electromigration causing anelastic deformation of glass when sending electric current through it
<whitequark>
that sounds plausible, but...
<whitequark>
"Conduction mechanism in ionic glasses is still considered one of the great challenges in physics and chemistry of glasses [A. Bunde, K. Funke, and M. Ingram, Solid State Ionics 105, 1 (1998)]."
<DocScrutinizer05>
hahaha
<whitequark>
although, let me read it
<whitequark>
conduction in glasses.1,5 Nowadays, everybody seems to
<whitequark>
agree that ionic conduction in glasses, at least in the dc re-
<whitequark>
1,5matrix. However, the mechanism of such hopping is the
<whitequark>
to hopping of ions between localized states in the glass
<whitequark>
gime and in the ac regime at not too high frequencies, is due
<whitequark>
1,5
<whitequark>
subject of many controversies.
* DocScrutinizer05
thinks of a glass rod with two steel wires along it
<DocScrutinizer05>
then heating it up till it starts conducting, and feeding a good current through it, not axially
<DocScrutinizer05>
should bend, eh?
<whitequark>
interesting, it suggests that the ions in glass may act as charge carriers in semiconductors (!)
<whitequark>
with a bandgap region
<whitequark>
hm
<whitequark>
I dunno, it well might
<DocScrutinizer05>
hehe, glass, the hottest semiconductor ever
<whitequark>
ah, no, the semiconductor thing was actually ruled out
<whitequark>
see that white lever in bottom right corner? that's how. it kinda rotates around on its axis
<whitequark>
on the spent cartridge it's in far right position. on the new one, in the far left
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<larsc>
apelete: that "... busy" messages are not normal, unless you have debugging enabled in the dma framework
<larsc>
apelete: you don't need a filter function, all channels can be used for everything
<whitequark>
it is amazing how much better this laser printer now prints, now that I have cleaned the drum thoroughly
<whitequark>
by the way, the manual says you should do it with dry cotton swab, but it had something like 0.2mm of toner attached to it in some places, so I went for a wet cloth
<larsc>
a friend of me who works as a IT service tech recently told me that she was asked why the laser printer even needs toner, apparently the person who was asking was under the impression that the printer would use the laser to burn the paper
<whitequark>
well, it's not a completely outlandish concept
<whitequark>
I mean, if the person doesn't have tech as their core competency, I don't see anything wrong with that guess. Internals of laser printers are not exactly trivial, especially to laymen.
<larsc>
yea, I thought it was funny who the name is misleading
<larsc>
for a inkjet printer the name tells you basically who it works
<whitequark>
that would also explain why are they so noisy and need sometimes several minuets to start up!
<viric>
do laser printers actually have a laser? :)
<viric>
I never tried to understand how it works
<whitequark>
viric: it's conceptually simple. it has a drum covered by selenium inside and a high-voltage generator
<whitequark>
initially, the entire drum surface is charged. then, a rotating mirror and a laser are used to direct light to those areas which need to be white, discharging them via the photovoltaic effect
<viric>
I thought the drawing wouldn't involve mechanical parts
<whitequark>
then, the toner is fed to the drum with another rotating cylinder, and the toner clings to the drum where the latter is charged
<viric>
mechanical moving parts. :)
<whitequark>
then, paper is pressed against the toner, transferring it to the paper
<viric>
I knew the static electricity part. But not how that is achieved.
<whitequark>
then, paper is fed through two hot cylinders pressed against each other, melting the toner and making the paper absorb it
<viric>
in most printers, you have to change toner + drum, right?
<whitequark>
btw, toner is usually polystyrene + soot
<whitequark>
hm
<whitequark>
I would think toner is charged too
<whitequark>
although it would not be strictly necessary (charge your hairbrush and pick up some uncharged pieces of paper with it)
<whitequark>
apparently when you move the hairbrush near paper, it polarizes the paper, collecting the opposite charge on the side near to hairbrush, and same charge on the far side
<whitequark>
then, opposite charges attract, and the paper clinges to hairbrush
<viric>
the toner has to be well produced, for humidity not to play a major role
<viric>
I remember playing with that with a balloon
<whitequark>
as I understand it, this clinging is favorable, because it spreads the charge over higher volume => an increase in entropy
<whitequark>
yes, toner needs to have very small particles and be very dry.
<whitequark>
although, toner is very highly hydrophobic
<viric>
and I never understood how then the toner doesn't fall from the paper
<whitequark>
van der Waals forces
<whitequark>
if nothing else, they'd be enough to keep it there
<viric>
if you use an eraser, you can't erase laser printed paper
<viric>
it looks like having a thin layer covering all.
<viric>
transparent.
<whitequark>
ah, you mean after it exits the printer? as I've said, it is melted
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<viric>
auhm
<whitequark>
the paper with attached toner is rolled through two hot cylinders, which melt the toner and force it into the pores of the paper
<viric>
ok
<viric>
that's the part of the printer with the label "this will get very hot"?
<whitequark>
yes
<whitequark>
and the reason paper exiting the printer is warm
<whitequark>
btw, there's a very funny story in Russian about the toner being hydrophobic
<wpwrak>
but ... how cold they miss the potential use for kendo ?
<wpwrak>
also, small children could use it as an umbrella
<wpwrak>
and when bagged, you should be able to play ping-pong with it
<wpwrak>
well, or just folded
<eintopf>
:D
<eintopf>
umbrella
<eintopf>
wpwrak: all missed functions ;)
<wpwrak>
and regarding military use, it's kinda nice that, if you should fail to decapitate your enemies with one swift blow, you can also use it to saw through their neck :)
<eintopf>
metal saw ;)
<eintopf>
some of my friends bought some of them
<eintopf>
from another friend in china
<wpwrak>
and now they're all day in the garden / woods, digging/hacking/climbing/hammering/... ? :)
<wpwrak>
ah, it can be used as a frying pan, too
<eintopf>
no, but at camping ;) they dig a ditch around their tent
<wpwrak>
just because now they can ;-)
<eintopf>
oh yes :)
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<wpwrak>
ah, i finally figured out what the "isoltion belt" is. it's for bush fires. to make a barrier without combustible material.
<eintopf>
wpwrak: you can also use it as paddle
<eintopf>
it's more than a swiss knife ;)
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<wpwrak>
paddle sounds smallish. they call it an "oar" ;-) (though the video shows it being used as a paddle)
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<DocScrutinizer05>
can opener looks like they're using it the wrong way. Probably better cut can into 2 halves
<larsc>
maybe it's a trick, say that all the speed cameras are damanged to get extra cash ;)
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<laigualdad>
i am looking for some recommendations for a bluetooth usb adapter that i can use with GNU/Linux (debian), without resorting to nonfree repos. am i in the right channel?
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<larsc>
maybe
<larsc>
it's not one of the core topics, but somebody might happen to know this
<laigualdad>
ok :)
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<pcercuei>
Bluetooth USB adapters are regular HID devices AFAIK
<whitequark>
no, they are not, they have the USB Bluetooth class
<whitequark>
the radio adapters which are HID devices are somewhat more common and not bluetooth
<whitequark>
and have the advantage that they don't need setup, or suffer from a horrible delay of several seconds on wakeup
<pcercuei>
ok
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<apelete>
larsc: hi
<larsc>
hi
<apelete>
larsc: about dma_channel_request, should the driver request two seperate channels for rxfifo and txfifo or a single one for both rxtx ?
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<apelete>
larsc: I've seen both ways in other drivers, don't know which one to do for the mmc driver
<larsc>
since we'll never do both at the same time one should be fine
<apelete>
interesting, so it's not possible to read and write from mmc at the same time ?
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<larsc>
not as far as I know
<larsc>
you have one data line, and it either transmits or receives
<apelete>
right, saw that in the datasheet actually, should have paid attention
<apelete>
larsc: ok, so I'm going to look at read_data() and write_data() now
<apelete>
larsc: I guess a good way to handle this would be to write seperate functions to handle dma transfers and insert them in read_data and write_data, like in davinci_mmc.c
<larsc>
yes
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<nicksydney>
morning / afternoon / evening lads
<larsc>
there is a short word which means all three of them: moin