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Stuff happening

am .

The HUG lab has been busy all week.

The V1.3 cells in differential mode are waiting for a nice isothermal box to shield it from Ambient temperature differences that may have been creating falsely positive data.  The new boxes are fabricated and the controls and instrumentation are being put in place.  Then we will test them and see how well they hold a constant temperature inside.

 

 

The Helmholtz coils will be incorporated around the V 1.3 cells once the cells are in these boxes. That's the only way to know that we are seeing meaningful temperature differences.

 

The Multiwire test is at the top of the calibrated range on input power and running at very near the top of the intended temperature in the cell.  And it is just starting, at that temeprature (450+ C) to show a possibly meaningful excess power reading that seems to be increasing exponentially with the temperature.  We tried putting a water jacket around the outer shell to help cool it and allow it to run at higher temperatures, but our water bath was room temp and didn't enhance the cooling at all.  Cooling the water down to 15C does not seem to helping either.  We possibly need to get the wire up over 500, which in the glass cells with direct heating can happen easily.  

Meanwhile, Paul and Wes have been tuning up the three slightly different versions of the vacuum bottle calorimeters.  The third version totally enclosed in a 2 inch thick foam jacket is definitely the most stable.  

The job largely consists of tuning PID controls and testing the thermal response to minimize the control noise under different conditions.  Sometimes it isn't terribly straightforward.

 

On Thursday, a group of us went to visit St Cloud State University, which is the closest major university to us.  There is a theoretical physicist we chatted with and wonderful, integrated science and engineering facility that we toured.  They have the closest SEM to our location and it has a working EDS.  Hopefully we will be able to take advantage of it, now that we know it is there.

And, finally, a new experiment to rule out the Langmuir effect as a possible explanation for the higher temperature on the glass has caught out attention.  We will post more on that soon.

 

 

Comments   

 
0 #8 Robert Greenyer 2013-10-10 19:03
@AlanG

Thanks again for the contribution
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0 #7 Edwin Pell 2013-10-03 23:00
Everything is working!
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0 #6 Malachi Heder 2013-09-30 14:40
@ Ed Pell

It is not really controlled. It is just limited by the vacuum specifications. It is around 0.6-0.8 mbar currently.
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0 #5 AlanG 2013-09-30 02:15
Regarding the Langmuir experiment, there's a very useful paper on Glass-hydrogen catalysis, studied in detail at:

eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/24735/1/9%281%29_P42-54.pdf

A key experiment (described at pg. 50) demonstrated that trace amounts of water vapor will stop the catalysis, and removing the contamination by vacuum will quickly restore it. This has consequences for the cell calibration protocol.
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0 #4 Edwin Pell 2013-09-29 00:45
@Ecco, I see your point about the vacuum.

@MFMP, how is the vacuum controlled in this experiment?
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0 #3 Ecco 2013-09-28 23:00
@Edwin Pell: as for the multiwire experiment, internal temperature increased abnormally for a while when power got increased to 32W because dynamic vacuum was stopped for a while at the same time. Not sure about the exact dynamics involved though.


http://i.imgur.com/7tUSyLf.png

I find more interesting that apparently there might be a clear correlation between loading (wire resistance) and temperature (it would be the first time this is actually demonstrated).. . if it only wasn't for the recently installed rubber hose which is cooling the temperature of the outer shell of the CTC cell (which by overheating less should in turn cause the inner core to get to cool too) and adding more variables to what is actually happening, though this was intended for getting more reliable output power readings from the calorimeter.

It takes quite a lot of time to deload completely these wires, by the way. However, I think MFMP should keep applying dynamic vacuum and heat until wire resistance goes back to its original value. Demonstrating that deloading hydrogen completely disables the anomalous heating effect is as important as showing that there is a one when the wires are loaded.

This is assuming that the wires are producing excess power, though. Due to some issues it is still uncertain whether they really are.

@MFMP: if the wires do really keep producing excess power under controlled dynamic vacuum for such a long time, then you could calibrate fresh wires under vacuum instead of having to use a different inner core with inert wires. This seems at first the same as the v1.3 protocol with the glass cells, but I think the CTC is much more suited for this job, since core temperature for output power calculations is indirectly measured (with the inner tube RTD) and opaque tubes are used (no issues with transmittance).
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+3 #2 Edwin Pell 2013-09-28 02:01
Thanks for the great update.

Folks in Minnesota know rigid foam insulation. :) Staggered joints beautiful.

[add] You have turned it into a Seebeck calorimeter. Hopefully putting an end to many uncertainties. I'm excited.

[add] The multiwire is showing 1.5 watts (4 degrees) of internal power during the first five hours after the step up to 460 degrees. This is almost like an oven experiment. The temperature is varied and the power produced by the sample is measured. There is no concern that somehow part of the applied current/voltage is falsely showing up as excess heat. Here only heat is applied. The current/voltage is isolated from the three wire sample. They are only connected in terms of temperature. Also we have explicit values for temperature!!!!
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0 #1 Ged 2013-09-27 22:49
Really nifty update guys. It's fun coming back to see how steady the progress and evolution of the methods has been.
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