Does anybody know what temperature toner transitions from solid to liquid ?
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Homebrew_PCBs@yahoogroups.comFrom:
novost@...: Mon, 14 Jan 2008 07:50:54 +0000Subject: [Homebrew_PCBs] Re: Epson R285
At 6:41 am ((PST)) Sun Jan 13, 2008, in Digest 2374 Stefan Trethan wrote:>[snip]>I also see the wrinkling when put in water, but i believe this is>different to the thermal expansion/contraction. Paper tends to get a>lot larger when taking up water.This is because it is made of fibres of cellulose, a long-chaincarbohydrate molecule, which absorb the water and swell upin all directions - but only the X & Y directions are particularlynoticeable. Water also loosens the bonds between fibresleading to permanent effects, such as the wrinkling of apreviously smoothly calendered sheet due to the disturbanceof the fibres being retained on drying.>[snip] It is different to your fingers getting all>wrinkly by the way,Not very different, except that skin has a high content ofstructural protein rather than carbohydrate. Proteinsgenerally have quite a high affinity for water.>this is because the salty water inside you is>drawn out into the less salty water on the outside,Not true, body membranes are quite retentive of electrolytes:the presence of salt in sweat is only because the glandsactively pump out the ions (and the water follows) notbecause the salt leaks from your body.Otherwise bathing would be a very risky activity rather thana pleasure, a pastime and a sport.As a further example of this, consider death by drowning.(That's not a recommendation of a course of action, btw ;-).If a child drowns in fresh water and is resuscitated there isstill a possibility of death through electrolyte imbalancefrom the amount of water which has passed through thethin lung membrane, diluting the child's small blood.volume.If a person drowns in sea water and is resuscitated thereis still a risk of secondary drowning caused by saltyresidues accumulating water out of the bloodstream.In both these cases the water chases the electrolytes,the "salt" doesn't move: look up "osmosis".>not because of your skin expanding>(although it may do that, too).Nope, that's exactly what it is.The skin is fairly waterproof, so that we don't leak away,and relatively dry on the outside since most of us live in alow RH atmosphere. (There are comfort and health problemswith living in a high humidity environment.)So the outer layer, high in the protein keratin, has a lowerhydration level than if it were in equilibrium contact with water.Given prolonged contact with water, there isn't enough realestate on your body to accommodate the skin's expansion inarea but since your skin is anchored in place it has to wrinklerather than sliding off one end or the other.>I'm told if you bathe in very salty water (e.g. dead sea)>this effect does not occur.>I am not certain if this is a myth or true.The effect can be true and your explanation a myth:it is the high osmotic pressure of the salt water thatcounteracts the hydrophilic nature of the skin proteinrestricting any water absorbtion to a level below whichwrinkling is evident.Regards, LenW-- From Yahoo! Groups Help: ... trim all the irrelevant quoted textout of your message (as a courtesy to the other members ofthe group to make the digest easier to read).
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