MIZUNO REPLICATION AND MATERIALS ONLY

Please note slight contamination of the gas is not a problem at all. It is not needed to vacuum that thoroughly to get excess.

Contamination will usually only cause increased geiger readings.

If i have well understood according to me356 explanation it is a surface phenomenom.

In this way, why don't leave nitrogen inside the lattice when you add hydrogen/deuterium ? it should avoid the H2 penetration not allowed by the author ?

Quote from magicsound

My replies to me356 are inline below, with further comments to follow

The filling of the cell was done carefully, using three calibrated steps of isolated volumes between the gas cylinder and the cell. The amount of gas is therefore well controlled. In this case it was the amount of D2 that produced 250 Pa of pressure in the cell with no mesh during repeated calibration of this process.

This seems to be the most likely explanation. One thought: he meshes were packed in individual zip-lock bags, where they remained for weeks or months prior to my use. The references below suggest that under some conditions Palladium might strip hydrogen directly from polyethylene. Perhaps Alan Smith will comment on this.

2 There was outgasing of the reactor in some way

There is always some outgasing from this reactor at 250C. Past analysis by mass spec. showed this to be substantially nitrogen, which is present in stainless steels from the foundry process. Typically this is 3-5 Pa/hr after settling, in line with what is currently shown in the chart below.

References:

From https://link.springer.com/article/10.1007/s11244-021-01452-x

Ali et al. showed that dehydrogenation beyond equilibrium was possible using a catalytic reactor with a palladium-silver tubular membrane to separate the produced hydrogen in-situ.

From

https://www.science.org/doi/10.1126/science.add1088

Conk et al. developed a preliminary method to produce propylene from a sequence of reactions between waste polyethylene and fresh ethylene. Specifically, the process involves a small extent of desaturation of each polyethylene chain by a dehydrogenation catalyst,

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It is because any pressure change will affect the reaction. Also nitrogen content was very small. But gas that is coming from yet unknown source is unwanted. It was already probably in the lattice. Lattice saturated with hydrogen which we suppose it is (will be likely determined by Alan after the run) will not produce any excess.

Quote from me356

better to ship in a sealed container with argon.

Yes, that would be ideal but not easy. My first thought is to cover the prepared mesh with sheets of Al kitchen foil and eliminate the plastic bags.

Unfortunately my mass spec system is at MKS for service, but I do have a combustible gas detector that's sensitive for hydrogen. Here's video of a quick test that seems to confirm that long exposure to the palladium-coated mesh has caused outgassing from the polyethylene bag. The bag from three months ago seemed to have more of the effect that the one received two weeks ago, so length of exposure is a factor.

MR6 PolyBag gas test

This is a quick test of polyethylene out-gassing after long contact with Palladium. Combustible gas was detected, composition unknown but probably hydrogen.

www.youtube.com

Wow, that is great finding!

RobertBryant Good find, Fig.1 tells the tale. Pd really sucks (H, that is)...

Do you have some ideas how to package the meshes? Which materials/products to exclude?

Quote from Alan Smith

Daniel_G

Any luck with those pictures of the 'flat' reactor?

Here is a photo before it went to the welders.

Low-energy X-rays will also cross-link long-chain hydrocarbons with release of hydrogen at the cross-link sites. So maybe excluding UV is not enough.

Will have the same influence between unsaturated or saturated oil as paraffin for example ?

Quote from Alan Smith

Low-energy X-rays will also cross-link long-chain hydrocarbons with release of hydrogen at the cross-link sites. So maybe excluding UV is not enough.

Quote from Cydonia

ill have the same influence between unsaturated or saturated oil as paraffin for example ?

Yes it will.

It is important to remember that there is something else in the packaging and pretty much everywhere, Water. Ionizing radiation effects on water molecules goes like this, As you can see, there is not only potential for the release of (initially) monatomic hydrogen but also the release of OH radicals, which are very reactive.

H2O → e−+H2O+H2O → e−+H2O+
H2O∗ → ∙H+∙OHH2O∗ → •H+•OH

H2O++H2O → H3O++∙OH

There are more potential steps - but these are the most interesting ones for this discussion.

Well, probably magicsound should do directly the "magic" copper covering at home to avoid that, more more simple.

Quote from Alan Smith

Yes it will.

It is important to remember that there is something else in the packaging and pretty much everywhere, Water. Ionizing radiation effects on water molecules goes like this, As you can see, there is not only potential for the release of (initially) monatomic hydrogen but also the release of OH radicals, which are very reactive.

H2O → e−+H2O+H2O → e−+H2O+
H2O∗ → ∙H+∙OHH2O∗ → •H+•OH

H2O++H2O → H3O++∙OH

There are more potential steps - but these are the most interesting ones for this discussion.

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Could one take advantage of the plastic bag packaging, instead of avoiding it?

Quote from me356

Do you have some ideas how to package the meshes? Which materials/products to exclude?

I suggest covering the mesh both sides with Aluminium kitchen foil and avoid direct contact with polyethylene or other plastics. This is standard practice for handling samples for SEM analysis, and leaves no residue on the sample surfaces.

Then the covered mesh sheets can be slid into a paper envelope. Direct contact of a sample with paper often leaves a residue of calcium, but the Al foil will prevent that.

I do not know if this would help, but you can buy bags used for shipping computer components.

ULINE - Shipping Boxes, Shipping Supplies, Packaging Materials, Packing Supplies

The problem is a bit more subtle than some of the comments above reflect. According to me356, if the Pd is saturated with H prior to heating, the activation process will not happen because the lattice has already been distorted or changed in a way that inhibits the reaction.

Based on my simple test video posted yesterday, hydrogen is stripped from the plastic by direct contact with the highly catalytic Pd. Although this is a slow process at ambient temp, the evolving hydrogen will immediately be absorbed by the Pd, and will accumulate over time, continuing until some equilibrium state is reached. From the MR6-2 evidence, the amount of H absorbed this way can be substantial give enough time.

Those meshes were stored in the sealed bags for about 3 months prior to use, and out-gassing at 250C yielded about seven times the amount added to the cell at the beginning of the run. The terminal pressure after 24 hrs was over 1800 Pa, while only 250 Pa of D2 was added to begin the test. Yesterday afternoon I unloaded the cell with vacuum at 250C, reaching 3E-5 Torr but only after 5 hours of bake-out. That pressure was stable over night, so atmospheric leakage can be ruled out as a cause of the unexpected pressure during the experiment.

Are the meshes permanently damaged by the hydrogen loading, or is there a chance that they will work after a bakeout step of the hydrogen?

Quote from Bahn

Are the meshes permanently damaged by the hydrogen loading, or is there a chance that they will work after a bakeout step of the hydrogen?

According to me356 the mesh may work after bakeout, though at reduced level. I'm finishing my current test by heating back to 250C after the deloading process. If the hydrogen is truly gone, there should be little if any rise in pressure. Currently at 175C the pressure is still below the 10 Pa measurement limit.