La Folia

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  1. Workshop space Chicago - moving

    Cairo, Illinois? ...Consider flying from Midway on Southwest.
  2. Workshop space Chicago - moving

    Seriously, not wanting to discourage you, just so you know, Chicago is BIG, and traffic can be slower than Miami evacuating in a hurricane. So you don't want to go very far if you can help it.
  3. Workshop space Chicago - moving

    You could always go deer hunting, then butcher the carcass in the living room -- just to break in the new digs a little. After that shock a few shavings and a little spilled varnish and tools and wood everywhere will seem like nothing.
  4. Login attempts of would-be hackers

    OK, mine was really hard, but now it's impossible to guess.
  5. Secrets in the wood (Stradivari's maple)

    The changes in weight are small, but the compositional changes are quite large. The compositional data are in Table S10. Look for the supporting information (SI).
  6. Case humidifiers

    How many kg of air is in one of your cases?
  7. Case humidifiers

    In a word, no. They can adsorb water at relatively low RH. It just depends on the material. By the way, the last graph that you posted gives evidence that your humidity meter is reading correctly. The ambient RH dropped as the ambient temperature rose. The fact that the RH goes up with increased temperature is proof that something is desorbing water. There is no other possibility. All the evidence that you posted shows that something in the shell or the padding is desorbing and adsorbing water. One other person suggested that there could also be condensation of water in the outer layers of the case in cold weather. Although adsorption is taking place, condensation is also possible.
  8. Case humidifiers

    David, Musafia's cooling results are just the opposite of the heating experiments, and perfectly reasonable if something if outer layers of wood or insulation were absorbing and desorbing moisture. But it's really interesting that your results show the opposite. Experimental error was mentioned in passing, but all bets are off if the data are wrong. Maybe we should have paid more attention to that. I'm not sure a relative humidity meter (of unspecified design) would necessarily give correct results under transient temperature conditions. Needless to say, it's essential to read the directions and ensure that the instruments are working correctly. It would help to test the equipment in a completely dry, closed metal (not iron) or glass vessel.
  9. Case humidifiers

    Well, you asked which wood I was referring to. I said that in a closed system with no air, the wood (in the violin) would not lose or gain moisture. If there is no wood in the case, then it isn't a consideration, is it?
  10. Case humidifiers

    If you heat air in a closed system, the RH goes down; if you cool it, the RH goes up. If the RH does not behave like that, the system is not closed. If you don't accept that, then I can't help you. Sorry. I'm doing this on my own time.
  11. Case humidifiers

    Well, you could try to buffer the relative humidity with hygroscopic materials (or water in the humifier). That can compensate for case leakage, but it does add kinetic complications of nonequilibrium temperature gradients. I meant the wood of the violin, but to be sure, the wood in the case is probably part of the consideration too.
  12. Case humidifiers

    Something in the case (or the wood in the case) released water when it was heated. I don't think there is any other possible interpretation. That was also GeorgeH's conclusion. Please, let's not argue that again.
  13. Case humidifiers

    My ideal would be a sealed case with no absorbing materials and no extraneous space (i.e., no air). Under these conditions, wood would neither absorb nor release moisture. Of course there is a large air space in any case, and in the violin itself, but my sense of it is that this is relatively unimportant. Absorbing materials and a and humidifier would complicate the considerations, but may be unavoidable or desirable under certain conditions.
  14. Case humidifiers

    In the absence of absorbing material or liquid water, the RH will go up when the case is cooled. The actual behavior in a case is complicated and somewhat unpredictable, since different parts of the case (including humidifier) cool or heat at different rates. It also depends on ambient RH and temperature. Mr. Musafia has shown that case materials can release humidity into the case. The reverse is also true. It must also be able to absorb humidity. In the case of cooling, I would usually expect the reverse of what Mr. Musafia found for heating: i.e., a reduction in RH. A humifier containing liquid water can also absorb moisture. It just depends on temperature of the humidifier, size of holes, etc.
  15. Dart-shaped viola case?

    Yes, I'm actually rather suprised that cases absorb and release so much moisture.