I swear I've heard about this before... is this one of those stories that emerges about a technology that never seems to enter the market? That "super slick" coating for condiment container interiors is another that springs to mind.
Fluids can remain subbornly un-mixed, over large distances and for long times. Given that brine is heavier than seawater, it will almost certainly tend to sink and flow along bathymetric contours, perhaps pooling in local low spots. And sealife can be exceedingly sensitive to changes in temperature, ion density, salt content, etc.
This reminds me of a book in which an ecologist described a discussion with a chemist over the concentration of some pollutant in seawater. Roughly, "Assuming a well-mixed solution..." starts the chemist. "How are you planning to stir the oceans?" asks the ecologist....
> But that doesn’t mean that there are no other ways of getting better output for our energy. The total process of desalination turns out to require three to four times the theoretical minimal energy use, since the salt water must be pumped and pretreated, the membranes maintained, and the resulting brine handled afterwards. Some of these things might be amenable to further improvements, and there has been work put into developing membranes that don’t clog up as easily or better pre-filtering of biological materials.
http://arstechnica.com/science/2011/08/desalinization-is-thi...
More: http://science.sciencemag.org/content/333/6043/712
https://www.researchgate.net/profile/Menachem_Elimelech/publ...
> Based on thermodynamic principles and practical kinetic requirements, the theoretical minimal energy for desalination with FO is always higher than that without FO. In other words, using FO cannot reduce the minimum energy of separation.
https://www.researchgate.net/profile/Shihong_Lin/publication...
The idea behind forward osmosis is to replace the salt in water with some other solute, like sugar. A strict 1-particle-to-1-particle replacement can (I think) have arbitrarily low free energy cost, but then you're just stuck with sugar water instead of salt water. In certain special cases this is fine (like for emergency water generation at sea, when you don't mind drinking sugar water). Insofar as low levels of sugar can't be tasted, and insofar as you have access to free sugar, you can avoid the energetic cost of removing some of the salt by replacing it with sugar. But I don't think this is very much before it becomes noticeable, and sugar isn't free.
If you happen to have excess thermal energy from some source, there are also ways to harvest some of this using forward osmosis, but this is really just another way to smuggle in free energy. In principle, you could use the heat gradient to generate electricity and then use that to power normal reverse osmosis, although which is more efficient will depend on the details of your equipment losses.
Even better, it can have a (theoretical) energy gain if you use a substance with a lower heat of mixing than (sea) salt and water.
The surface is fragile, because it's composed of tiny spikes. Rubbing will destroy it. It's hard to fix this, because the property that makes it useful is the same as the one that makes it fragile.
> But it has been difficult to produce large quantities of single-layer graphene using existing methods, such as chemical vapour deposition (CVD). Current production routes are also quite costly.
> On the other hand, said Dr Nair, "graphene oxide can be produced by simple oxidation in the lab".
> "In terms of scalability and the cost of the material, graphene oxide has a potential advantage over single-layered graphene."
E.g. look at how long it took to develop digital cameras, flat screen TVs, etc.
I'm not saying it shouldn't take time to develop these things, but surely the 30-40 year timeline is significantly reduced due to information sharing today?
Check out the book "Skunk Works" sometime and marvel at what they managed to do on the frontiers with such small numbers of people and crappy computers (with relatively small budgets and tight deadlines to boot).
Peter Thiel riffs on this idea a lot. Despite our incredible advances in computing and networks, it seems like progress in everything else has slowed down. (Randomly found video with his basic stack of points: http://bigthink.com/embeds/video_idea/48434?width=512&height...)
Another example, consider how long it takes to build any skyscraper in the US. This isn't even new tech, it's well understood, but it still takes a long time from planning to legal stuff to the actual construction. And yet there's a guy in China who builds other kinds of skyscrapers at a rate of two floors per day. Slowness is not a fundamental thing.
If this is made the makers better warn first or that ketchup is going to fly out like a rocket.