Moreno

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  1. The future of IP telephony

    I think this problem is more relevant to standardization rather than technological revolution. The turn is on phone manufacturers (both stationary and mobile) side. All they need to do is just to manufacture all the stationary phones in the hybrid version - capable support both PTSN and VoIP equally well. Such phones have to be maintenance free, so people wouldn't need to download any updates or care about antivirus - all this have to be done at the server side. Such hybrid phones need to support Skype, whatsapp and variety of other Internet programs. Once everyone will have a hybrid phone PTSN can either die slowly or people may all abandon it in X day (like it already happened to analog TV in some countries). The same is about mobile phones. Mobile manufacturers need to preinstall all the phones to support Skype, whatsapp etc, equally well as a regular communication protocols. Then people would be able to pay for Internet only and speak for free. Voice traffic takes just insignificant amount of total Internet traffic.
  2. Let say I want to obtain a semiconductor with mixed electron-hole conductivity by doping. Typically it's not going to succeed because donor and acceptor admixtures (electrons and holes) are going to recombine with each other. How can we prevent recombination and preserve mixed conductivity? It is claimed that free electron and a hole (valence electron) cannot recombine if they have aligned spins. Can there be a material in which all the free electrons and holes have aligned spins? Can this state (and mixed conductivity) stay for indefinitely long period of time?
  3. Band gap in metals

    So, their valence band is completely full and their conduction band is half-full? It comes in sharp contrast with conductivity in semiconductors. And why II group metals are hole conductors? Their valence band is full as well?
  4. Genetic engineering?
  5. The future of IP telephony

    What type of inscription is unbreakable at modern technology?
  6. Band gap in metals

    Under which conditions a materials may have multiple conduction bands separated by band gap? For example: http://www.nature.com/articles/nmat4430 Possibly this effect can be observed in some metals as well.
  7. The future of IP telephony

    How exactly?
  8. The future of IP telephony

    I think it is an interesting question whether wireless will completely replace cables someday. I afraid that in order for this to happen a principally new type of technology have to be developed, based on principally different physical principles. Desirably, it suppose to be completely invulnerable to interference and make cell towers obsolete. Maybe something based on quantum mechanics? However, I afraid that such type of an "ideal" communication technology may create a huge social dangers which include at least: 1) Communications of wrongdoers which cannot be intercepted. 2) Remotely controlled bombs and suicide drones which cannot be jammed. 3) Electronic bags which cannot be jammed or detected. In one word I'm not sure if humanity is ready for that type of technology yet.
  9. It is claimed that solar cell efficiency record achieved 32.6% under one -sun. https://en.wikipedia.org/wiki/Solar_cell Would it be possible to achieve the same efficiency someday, for living plants with help of gene engineering? If yes, how much would it change our civilization? For example, prices for food, wood and biofuel? Would it become cost efficient base all energy production on biomass burning?
  10. Fast breeder reactors

    How good are heavy water thermal reactors at burning Thorium or Uranium 232? What are issues behind them aside heavy water price?
  11. Fast breeder reactors

    If chain reaction is their regular mode, what can happen even worse than that? How runaway can happen?
  12. Fast breeder reactors

    It seems some countries have more Plutonium they need. For example UK. https://www.theguardian.com/environment/2012/feb/02/nuclear-reactors-consume-radioactive-waste France only experimented with them. They had sodium-cooled fast reactor but turned it down for persistent accidents. Now they continue small-scale experiments with few types of fast reactors. Japan is exactly the same story. The only full-power operational fast reactor is in Russia. This one is a sodium-cooled, but Russia plans to develop lead-cooled reactors. Gas cooled rectors don't suppose to have the same problems, because in difference from sodium helium is an inert one.
  13. How safe are fast reactors in comparison to common water-cooled? Why nobody (except Russia and India) want to build them? There seem to be huge amount of fuel for them which is essentially free - Plutonium, Uranium 232, Thorium and thousand of tons of dangerous nuclear waste. All this could be efficiently burned in fast reactors with few nuclear waste remaining. What about gas-cooled fast reactors in particular? Why these reactors are so unpopular?
  14. The future of IP telephony

    https://it.toolbox.com/blogs/voipdesk/when-does-the-pstn-end-and-voip-take-over-022615
  15. The future of IP telephony

    At that frequency it is going to be a thing ray of IR radiation. At which exactly points on Earth a satellite suppose to send it?