News for US V 1.3

Sorry it's been awhile, folks. We just needed time to sort kinks in the V1.3 cell setup as well as make some headway on another version of cell for the concentric tube calorimeter (let's go with CTC and from now on, eh?). Paul also says the magic rule is to have 2 positive posts per every 1 negative post. So we'll just call the last US and update posts 1 negative entry. 

The kinks I mentioned were mild speed bumps compared to Monday's blowout since it was a simple reorganizing fix. Our 3 T_Amb sensors are stationed in the experiment hood but apparently our air flow doesn't isolate them from the cells well enough. This was apparent as the T_Amb average rose with W_NiCr for both cells. We have since installed new thermocouples that are just outside the hood and roughly on the same horizontal plane as the cells, but not close enough to vary with cell temp. Easy!

In regard to concentric tube cells, we believed the calibration data was tight enough to get going on some real cell action. I spent Tuesday afternoon trying to engineer the ceramic scaffolding inside the 1/4" tube. This design featured the same thick copper wire for the pass through; it's snug as a rug inside the ceramic insulation tube. Welding this 24 AWG (~0.4 mm dia.) copper with 32 AWG oxide wire(~0.2 mm dia.) also used in V1.3 cells isn't the easiest task under the sun, and getting the ball of molten metal to fit inside those ceramic rods is nigh impossible! Malachi gave it his all on Wednesday, but the results weren't much of an improvement. . .

I did get a chance to photo the process, though. The green Cu flame is pretty cool!

And there's the weld. Too big for the ceramic! This is just oxide and copper, not Celani-treated wire yet.

We settled on fiberglass insulation the whole way through and an epoxy-sealed ceramic stem on the far side of the Tee joint. This should suffice to keep everything electrically insulated and Hydrogen tight!

The completed 1/4" reactor. We're using this for a new version of the CTC (I'll fill you in later). 

Here's a better look at the end of the cell. You are looking at the TSS (toothpick support system) to prevent the unruly passthrough wires and thermocouple from moving too much. 

However after our assembly of this reactor we realized we'd need a bellows valve and a pressure transducer for it to work. We'll charge it once with high pressure H2 and then seal it off to insert it into the CTC. We don't have any pressure transducers on hand so now we await their arrival. 

Curiouser and Curiouser 

Check out these two graphs, R_ox Vs W_NiCr for US1.3A and US1.3B respectively. The resistance in the active wire isn't behaving like it should as it decreases in US1.3B when we passively heat it with NiCr wire. That's the opposite of what we expect! We've seen comments on the issue but are in search of conclusive response as to what's going on in there. 

US1.3A R1_Ox and W1_NiCr. R1 is virtually static, as is expected.

But here in US1.3B R2_Ox is pretty well aligned with W2_NiCr.

Malachi had this to say earlier today, 

"@ Dieter

I see that the oxide wire in the Cell B is actually decreasing instead of increasing, like you would expect from a passively heated wire. The oxide wire in cell A is holding surprisingly constant, but it is increasing like we would expect. The resistance is calculated the same way for both cells, so I don't believe it's a software/computer issue. However, I recall in cells 1.0 and 1.1 that we saw opposite trends like this between two different celani wires (2 layer and a 14 layer). Again, these were different wires and now we have the exact wire from the same roll. Could there be this much discrepancy from two identical wires? We will be exploring this for a while today."

And our exploration has yielded few results as we can pull no answer from data analysis. 

What do you suppose is going on here? 

P.S.

Even though the data isn't a whole lot of fun, isn't it nice to see it in blog posts again?