Re: [time-nuts] Thunderbolt stability and ambient temperature
Chuck Harris wrote: Bruce Griffiths wrote: John That doesn't appear to reproduce what was claimed to have been observed at all. The input is more like a step function that switches from hot to cold. This allows the simulated bar to reach a steady state temperature distribution before decaying smoothly to a lower temperature. Bruce Humans are terrible witnesses when it comes to judging lengths of time, and degrees of temperature. That's probably why clocks and thermometers were invented. -Chuck Harris When I started this part of the thread I said that one of these days I want to try to make some measurements to see if I can document what I believe I have experienced. A few others seem to think they have experienced the same effect. I won't say that we couldn't possibly be wrong and it is some kind of illusion. The previous time I posted about this (elsewhere) the majority opinion was that I was wrong about what I thought I was experiencing. Before I quit, here's a little bit more info. By the time I carried the bar to the water, the hot end was probably barely red temp or not red at all. When I first noticed it I wasn't trying to suddenly quench the bar, just cool it off. The bar was nearly horizontal and I was passing it under a stream of cold water a bit at a time. It certainly produced steam but the steam never got near my hand and the increasing heat I felt was coming through the steel. I don't believe the steam was moving down the bar much either (possibly transferring the heat I felt.) Because of what I've experienced, now I tend to cool things by applying the water near my hand and working the water toward the hot end. I'll try to not drag this out by posting more on the subject unless I get some supporting data or if there are any specific questions. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt stability and ambient temperature
Rex skrev: J. Forster wrote: It has nothing to do with this. A long (length width) bar can simply be modeled as a long ladder of series resistors's and capacitors to ground: ---zzz---zzz---zzz ... ---zzz--- _|_ _|_ _|_ _|_ ___ ___ ___ ___ | |-|- ... |- If you put a rectangular pulse in the left end, it will emerge later and very much rounded at the right end. Either do the math or simulate it in Spice or with a handful of R's and C's and a pulse generator and scope. No inductors needed. PERIOD. That model fully accounts for your observations with the bar heated at one end. -John = Ok, but isn't that propagation rate constant? Obviously, the heat from the hot end will eventually propagate with some attenuation to the cold end. My observation was that shoving cold into the hot end seems to accelerate the propagation of heat toward the cold end. This model won't show that effect, will it? This would be a double step something like this: |--- | \ ---|\ + time | / || That 2nd opposite step won't make the first pulse propagate faster or with more apparent intensity, will it? No, you just perceive it to be related. If you had waited it would have happend anyway without the cooling period. Your cooling has nothing to do with the already heated wave. While the speed does depend on temperature, it is not that distinct effect. The cooling will also take that time to get through. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] GPS Week 1536 causing problems?
Fellow time-nuts, If you recall, when we hit GPS week 1524 (1024 + 500) we had issues with a few receivers that didn't handle their biased GPS week wrapping correctly. Then the arbitrary constant was 500. Now on Sunday the aribtrary constant of 512 occurs as we enter GPS week 1536 (1024 + 512), as calculated here: http://csrc.ucsd.edu/scripts/convertDate.cgi?time=1536+0 If you see any node having problem, it would be nice to know. Hopefully no node fails. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt stability and ambient temperature
Rex wrote: Humans are terrible witnesses when it comes to judging lengths of time, and degrees of temperature. That's probably why clocks and thermometers were invented. -Chuck Harris When I started this part of the thread I said that one of these days I want to try to make some measurements to see if I can document what I believe I have experienced. A few others seem to think they have experienced the same effect. I won't say that we couldn't possibly be wrong and it is some kind of illusion. The previous time I posted about this (elsewhere) the majority opinion was that I was wrong about what I thought I was experiencing. Rex, it isn't that you are wrong about what you thought you were experiencing, it is more that you mis interpreted the result. Time, as perceived by humans is variable. The old saying that time flies when you are having fun, it true from most people's perception. And time crawls when you are focusing on being in a hurry, as is often the case when working with red hot metal. I am certain that if you do the experiment with some more controls, you will discover that, if anything, the heat to your hand slows as a result of cooling the bar (horizontally in water). Here is how I would run an informal experiment: Put two identical bars in the forge fire, and let the ends heat to a nice orange heat. Turn on the water at the sink. Pick one bar up in your left hand, and the other in your right. Walk over to the sink, taking about the amount of time you did before, and hold the end of one bar in the water, and keep the other bar out of the water... and wait for it If the bar in the water becomes uncomfortable to hold before the one that is out of the water, you are on to something. I bet it won't. Before I quit, here's a little bit more info. By the time I carried the bar to the water, the hot end was probably barely red temp or not red at all. When I first noticed it I wasn't trying to suddenly quench the bar, just cool it off. The bar was nearly horizontal and I was passing it under a stream of cold water a bit at a time. It certainly produced steam but the steam never got near my hand and the increasing heat I felt was coming through the steel. I don't believe the steam was moving down the bar much either (possibly transferring the heat I felt.) The reason I mentioned the steam is when you are quenching a bar for the purpose of hardening it, you invariably dunk it straight down in a bucket of water. The steam can't help but rise up to whatever is holding the bar. Because of what I've experienced, now I tend to cool things by applying the water near my hand and working the water toward the hot end. Unless you are hardening the steel, you really shouldn't quench it in water. It tends to really mess with the end result. I'll try to not drag this out by posting more on the subject unless I get some supporting data or if there are any specific questions. I truly hope you aren't bothered by our rumination. We clearly are enjoying the subject. Thanks for bringing it up. -Chuck Harris ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Subject: Thunderbolt Stability and Ambient Temperature
This interesting discussion of heat conduction by members of the electronics community brings to mind that in the 1870's, Joseph Fourier, while analyzing the waveform of heat propagating around a metal ring, developed the elegant method of Fourier Analysis. If you have not seen his work and can locate a copy of Fourier's: The Analytical Theory of Heat, you might find it interesting to thumb through it. Bruce Hunter **Shop Dell’s full line of Laptops now starting at $349! (http://pr.atwola.com/promoclk/100126575x1221881320x1201406166/aol?redir=http:%2F%2 Fad.doubleclick.net%2Fclk%3B215218036%3B37264217%3Bz) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] E1938 PIC hex files?
I am beginning to think that the PIC in my Chinese Ebay 1938 is dead or at least injured. Does anyone have the hex files for this one? Blank PIC16C74As can be had and it may be worth my trying to program a new one. Nothing else seems to make it work and as the PIC seems to be asleep, I'm not sure that attempting to talk to it with the serial program is going to help me much, but I will try. The part number is: E1938-80002 Dan ac6ao ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Subject: Thunderbolt Stability and Ambient Temperature
On Fri, 12 Jun 2009 11:14:14 EDT, brucekar...@aol.com wrote: This interesting discussion of heat conduction by members of the electronics community brings to mind that in the 1870's, Joseph Fourier, while analyzing the waveform of heat propagating around a metal ring, developed the elegant method of Fourier Analysis. If you have not seen his work and can locate a copy of Fourier's: The Analytical Theory of Heat, you might find it interesting to thumb through it. Bruce Hunter ** A interesting discussion indeed! The Wiedemann-Franz Law may bring more light in this discussion. Gustav Wiedemann and Rudolph Franz found an empirical law of physics, concerning the ratio of the thermal conductivity (K) of a metal to its electrical conductivity (Ã), being a constant times the absolute temperature. Good and easy to understand descriptions can be found not only in: http://en.wikipedia.org/wiki/Wiedemann-Franz_law http://hyperphysics.phy-astr.gsu.edu/Hbase/thermo/thercond.html enjoy, Arnold ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt stability and ambient temperature
Chuck Harris wrote: I truly hope you aren't bothered by our rumination. We clearly are enjoying the subject. Thanks for bringing it up. -Chuck Harris No, not at all. I brought it up because what I think I saw doesn't make sense from anything I know. I already have a large list of partially-done projects, so I doubt if I'll get back to another look at this subject soon. If I ever do I'll try to post any results. -Rex ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] ARRL Summer FMT Announcement
The ARRL Summer FMT will be held on July 1. See attachment for details. -Mike- WA6ZTY FMT Announcement - 1 July 2009.pdf Description: Adobe PDF document ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] ARRL FMT
It's that time again. The ARRL Summer FMT will be held on July 1. See attachment for details. -Mike- WA6ZTY file://c:\program%20files\qualcomm\eudora\attach\FMT%20Announcement%20-%201%20July%202009.pdf FMT Announcement - 1 July 2009.pdf file://c:\program%20files\qualcomm\eudora\attach\FMT%20Announcement%20-%201%20July%202009.pdf FMT Announcement - 1 July 2009.pdf Had inline: 642800d.jpg___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
