• bevan@lemmy.nz
    link
    fedilink
    arrow-up
    2
    ·
    10 months ago

    This is odd. I run a similar but smaller facility in New Zealand (3 tanks). If the nitrogen supply fails we have about 18-20 days worth left in the tanks before they run dry. Even then I had a staff member checking every couple of days over Christmas anyway. I wrote an R script to analyse data from the tanks https://rhizobia.nz/r/N2-tanks.html to get a good idea of usage.

    Just strange to me that a much more well funded organisation didn’t do better.

    • RobotToaster@mander.xyz
      link
      fedilink
      arrow-up
      2
      ·
      10 months ago

      Just strange to me that a much more well funded organisation didn’t do better.

      I’m guessing the bureaucrats are very well funded.

    • IrritableOcelot@beehaw.org
      link
      fedilink
      arrow-up
      1
      ·
      10 months ago

      That is weird. I don’t think i’ve ever seen a sample dewar that couldn’t last two weeks, most are fine for a month or more. How the hell are they designing their sample storage system, that it’s only go of for four days? Are they insulating with Styrofoam?

    • jarfil@beehaw.org
      link
      fedilink
      arrow-up
      0
      ·
      10 months ago

      That’s interesting. May I ask you a few questions?

      Why are you storing in the gas phase?

      Some temperature spiking is normal, but it should not exceed the glass transition temperature of about -130°C.

      Glass transition of what, the samples? Sample containers? …?

      “one-fill all-fill” (OFAF) to work. OFAF fills all tanks sequentially once any one triggers the process.

      What are the benefits of that?

      From the usage graphs, why does it seem like Tank 1 is using the most nitrogen, even though Tank 3 is getting accessed the most? Shouldn’t Tank 3 have higher losses?

      • IrritableOcelot@beehaw.org
        link
        fedilink
        arrow-up
        1
        ·
        10 months ago

        I can answer questions 2 and (tentatively) 4!

        When freezing samples, they are cooled rapidly to form vitreous (noncrystalline) ice. If the ice warms enough (and that temp is still well below 0°C), it can transition into a crystalline form. This makes the ice expand and become spiky, which can damage proteins and cells.

        For differences in LN2 usage, not every dewar is created equal. Age, the degree of vacuum between the walls, and the distance between the inner and outer walls can substantially affect the thermal conductivity, and thus the boil-off. Differences in how they are capped (which by nature can’t be vacuum-insulated) can also change their efficiency.

    • Midnitte@beehaw.org
      link
      fedilink
      arrow-up
      0
      ·
      10 months ago

      You’d be surprised how many labs don’t do temperature monitoring, let alone data analysis on that to try and predict when that asset will fail