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Comment Re:The problem with CFC (Score 1) 211

not only that, but it isn't something that you keep using, so even if civilization continues, CFC's probably won't (at high levels). The consequences of high atmospheric CFC's are enough to push them out of use. It'll be like high powered omnidirectional TV and radio signals. Those stopped too, yet we continue.

Comment Re:Lots of work has been done here (Score 1) 62

LEDs will still have a pretty broad spectral response so you'd have overlap, and need quite a bit of gain. Try one of the taos colour sensing chips, those do RGB+all with programmable gain and digital output, it'll make the project pretty simple and much more repeatable. you can also do one clear NIR phototransistor with selectable filters for colours. That'd be manageable. For my project, I am using, currently, a clear phototransistor and illuminating the target with a specific LED colour. I think someone has done something pretty similar (but reflection rather than transmission) on instructables too, but I can't dig it up.

Comment Re:Hah! Take that, my bank! (Score 1) 497

TD bank in canada: 5-8 letters, no symbols. Sure you have to answer a few (random 3 of 5) quiz-of-your-life-history questions after, but really. Passwords must: - be 5 to 8 characters in length - not contain spaces or special characters (e.g. #, &, @)

Comment Re:It is a RO membrane, just a really good one (Score 5, Informative) 303

The abstract: "We show that nanometer-scale pores in single-layer freestanding graphene can effectively filter NaCl salt from water. Using classical molecular dynamics, we report the desalination performance of such membranes as a function of pore size, chemical functionalization, and applied pressure. Our results indicate that the membrane’s ability to prevent the salt passage depends critically on pore diameter with adequately sized pores allowing for water flow while blocking ions. Further, an investigation into the role of chemical functional groups bonded to the edges of graphene pores suggests that commonly occurring hydroxyl groups can roughly double the water flux thanks to their hydrophilic character. The increase in water flux comes at the expense of less consistent salt rejection performance, which we attribute to the ability of hydroxyl functional groups to substitute for water molecules in the hydration shell of the ions. Overall, our results indicate that the water permeability of this material is several orders of magnitude higher than conventional reverse osmosis membranes, and that nanoporous graphene may have a valuable role to play for water purification." Emphasis added for why, and the introduced problem

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