A silly (?) question to you chemists out there

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richardh08
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Re: A silly (?) question to you chemists out there

Post by richardh08 »

Using -60 +100 mesh MgAl instead of -250 mesh fixed the multiple report problem. As expected, it also increased the delay, from around 0.4 to 0.5s to 0.7 to 0.8s (using 3% NC as the binder).

However, the measurements don't give any clearer picture of what is going on than the result in my previous post. To go any further, I think I need to look at the behaviour of a wider variety of compositions.
Even when I'm wrong, I'm convincing.
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richardh08
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Re: A silly (?) question to you chemists out there

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I've spent most of today doing sums.

This morning I came across National Bureau of Standards Monograph 40, entitled 'Thermocouple Materials'. It's exactly what I've been looking for over the last couple of months; it discusses a wide range of thermocouples and lists detailed calibration curves for them, including the type G thermocouples I'm currently using. I've been able to refine my temperature estimates, though the improved calibration curve actually makes very little difference to the results.

Interestingly, it also discusses the W/Mo thermocouples that I was using a while back, and lists calibration data over the range from 0 to 2200°C. I was pleased to find out that my calibration curve, constructed from my own measurements and the partial data from the paper I found earlier, agrees quite closely.
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Lloyd
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Re: A silly (?) question to you chemists out there

Post by Lloyd »

Heh! "Independent research", with no knowledge of the others' findings, but with the same results! I love it.

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Re: A silly (?) question to you chemists out there

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I'm taking a bit of a break from the endless round of measuring temperatures to do a few other things that I've ignored for too long.

In a sense, this thread has reached its conclusion. It started with a question that turned out to be a pointer to the fact that my original temperature measurement techniques weren't giving the right answers. It's been a long road but I'm now fairly sure that the new thermocouples are giving accurate and meaningful data for a modest range of compositions. Whether that will be enough to answer the deeper questions about how crackle actually works remains to be seen.
Even when I'm wrong, I'm convincing.
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Lloyd
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Re: A silly (?) question to you chemists out there

Post by Lloyd »

I don't blame you a bit, Richard. Nor do I believe you'll 'abandon' the research. Curiosity knows no bounds! You just need a rest.

I'm taking one next week, at the Florida Pyrotechnic Arts Guild's 25th anniversary meeting!

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Re: A silly (?) question to you chemists out there

Post by sambo »

Ditto, but boy what tenacity! I look forward to nosing around your next endeavours ! Sam.
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biffo
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Re: A silly (?) question to you chemists out there

Post by biffo »

You really deserve a break Richard what sustained hard work.regards B
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richardh08
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Re: A silly (?) question to you chemists out there

Post by richardh08 »

Some might call it tenacity; others might describe me as stubborn and bl**dy minded. :lol:

I'll certainly keep going until I either get the answers I want or run out of things to try.

Lloyd, I'm quite envious of those of you who can go to the FPAG meet - I hope we'll get to hear an account of what it was like.
Even when I'm wrong, I'm convincing.
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