Apr. 4th, 2017

drwex: (WWFD)
Right now there's a lot of airplay being given to a discovery in the UK of which this headline is typical: "Graphene Sieve Makes Seawater Drinkable".

Um, no. It does not. That's not even close to what happened. What actually happened is some dudes in a lab have a theoretical solution to a really serious problem. It's a very interesting solution in that it appears to show how a particular set of structures and temperature control can permit a graphene-based system to filter very small salts from a liquid without significantly impeding water flow.

But let me list a few of the problems here:

  • There's more than just salts making seawater undrinkable. Desalination is an important and necessary step, but it's not sufficient.

  • The lab dudes haven't actually desalinated any water yet, never mind doing so at scale. Mass producing the necessary graphene structures and getting them to behave in real life the way the lab model says they can behave are unsolved problems.

  • The lab dudes haven't actually tested their innovation on any messy real-world molecules. Instead, they've run "molecular dynamic simulations". In English that means they wrote some computer programs to model how they think things will behave. I happen to work with a lot of very smart chemical engineers and talked with one who did a ton of MD simulation for his PhD. He pointed out that MD simulations involve a number of simplifying assumptions, which you have to tweak to make your computer codes run. How well the result aligns with reality is something still to be seen.

  • If you read the paper (you should - it's a good paper and it's linked from that Yahoo article) you see there are also interesting discussions of the role temperature plays. In lab simulations you can get temperature to behave exactly how you want; in the real world not so much.

  • Even if all the above works out, thermodynamics still exists. AFAICT the lab work does not calculate the energy needed to manufacture and operate this system. That alone could be too high (especially if precise temperature control is needed) to make it economically feasible at scale.


This is why things take 20-30 years to go from hairy lab prototypes to actual commercial systems and this thing isn't even at "hairy lab prototype" stage, yet. If you want to see the state of the art in actual desalination it's still RO, and the Israelis put the biggest RO plant in the world online a couple years ago.

So the news stories stating that this discovery is going to lead to (more) drinkable sea water are just wrong. Not fake, but just wrong.

See also Popehat's takedown of recent political wrong news which I won't repeat here. But having two extreme examples of this sort of thing cross my news feed in one morning prompted me to write. We now return you to the ongoing shitshow...
drwex: (WWFD)
I'd like my LJ-centric readers primarily to comment. I get far more comments there than here (dreamwidth).

Some of the people who migrated to DW after the LJ servers were initially moved into Russian territory, like myself, have been assiduously cross-posting and permitting comments there. Recently LJ pushed out a new set of terms, the only authoritative version of which is in Cyrillic. You can read their translation or Google's and you must agree to that translation prior to continuing to use your LJ account. At a minimum it seems weird to force me to agree to something that the author themselves asserts is non-authoritative.

People have used terms like "sketchy" to describe the agreement and the corporate behavior behind it. Nothing I read in either translation seemed particularly sketchy. And when you get down to it the fact that Putin's thugs now have physical access to the servers renders any user agreement moot. They'll take what they want and decide afterward how big a trail of bodies to leave.

Still, it's increasing the weight on the "get out of Dodge" side. Some people have reacted to that by cancelling and/or deleting their LJs. I'm likely to cancel my paid sub there once I de-lame. Another step has been to turn off comments on the LJ side, forcing people who want to comment to click through the link to the DW side where they can comment.

DW allows you to subscribe to, and give access to, LJ accounts so this behavior doesn't force anyone who wants to comment to create a DW account. The question, dear readers, is whether you'd object to or be less likely to comment if I took the same route and closed comments on the LJ side.

What say ye?

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