studiot

The first physical solitons were reported by the first man to investigate such phenomena Russell J S Report on Waves Rep. 14the Meet.Brit.Adv.Sci.,York,311-90. 1884 He also uncovered another interesting interaction property of non linear waves.

And just how does the farmer store this electricity ? I'm not saying that hydrogen is the be-all and end-all. We need multiple solutions to multiple problems and situations. According to the UK government calculator (MCS) 29% of solar is generated during the 6 months Oct - March and 71% in Apr - Sep , just the time the farmer will be growning crops, not ploughing.

Both "moving and travelling" your own words about the video you linked to. I have now had the opportunity to watch this video and have a couple of comments. 1) As a demonstration it is interesting but you need to be able to explain (not just state) what it demonstrates. 2) There is a mistake in the presenter's script at about 2 and a half minutes. He says " the pendulums fly out further and further as the rotation speed increases" The bobs appear to be suspended on rigid rods so how is this possible ? 3) Yes : The mechanism does show a wave travelling along the length of the shaft, being reflected at the far end and travelling back. Two waves not one. Yes: These two waves interfere to produce a standing wave, non linear but conventional. These are not solitons. According to my understanding the following definitons apply. For a given waveshape, the speed of propagation of a nonlinear wave depends upon its amplitude. Larger amplitude waves of the same shape travel faster than smaller amplitude waves. If the waveshape of a single nonlinear travelling pulse does not change as it propagates, it is called a (travelling) solitary wave. A travelling solitary wave can interfere with another wave of the same shape but going the other way to produce a standing solitary wave. But also and unlike linear waves, that all travel at the same speed, nonlinear waves of the same shape but different amplitudes have additional posiible modes of interaction. The larger amplitude and therefore faster, non linear wave, can overtake another nonlinear wave. When it catches the first smaller wave, there is a time of complicated interaction. If the two waves finally emerge as before, they are called solitons. Not all nonlinear waves have this property of the faster wave being able to 'pass through' the slower one. Now you did not answer my question about the hydraulic jump. Your title is about macroscopic phenomena and I was trying to help you with physical understanding using this macroscopic phenomenon. From what I can make out, such waves can occur in a phase space rather than physical space. So we need to distinguish clearly between the physical and the model representation.

I don't see however big or small the solar farm is offers any answer at all to my question which was How do you get the solar generated electricity to a machine that is out in the fields where there are no electric points ? This is something farm machinery has in common with the excavator I linked to.

And how would you get the output from your solar farm to the large, energy hungry, agricultural machinery of today ?

Indeed so. But there are pitfalls as with anything in this world. Storage as heat or electricity can only ever be short term as both dissipate with time and require auxiliary apparatus which is not self contained to distribute. Long term storage will require other methods (storage as some form of potential energy) into the forseeable future.

The OP has had the benefit of this and similar and better advice but is obviouly a worrier. Perhaps he / she has family video on those DVDs. Irreplaceable as I said.

I, for one, have plenty of totally irreplaceable video tapes and have learned the hard way that old photographs and cine films fade, old video develops droputs and eventually fails.......... That is one reason Hollywood is investing $billions in restoration techniques for stuff they did not save at the time.

I can't watch the video at the moment and it is , as you say, someone else's model. This is your thread so you should be offering your supporting development, not just copy/pasting other people's work. Do you understand the hydraulic jump ? The hydraulic jump behaves in a very similar way to the graph you showed. The jump is 'stationary' in that it always occurs in the same place for a fixed geometry. It builds up, rather like the sequence of coloured curves in your top sigmoid plot, at a fixed point on the horizontal axis, until there is a macroscopic 'quantum jump' in the water surface. But the water has to be flowing.

So you have a bunch of unexplained mathematics, including a velocity term that tends to unity (1) and a couple of graphs with their axes not labelled. How does this demonstrate that a soliton is standing still ? Are you not not confusing a stationary state in a plot with an entity standing still ?

You have to demonstrate this, not just claim it. As far as I understand the 'internal' mechanism of a soliton is such that it has to be in continual motion for the 'self - reinforcing' mechanism to operate. (That was also in your quote.) The only way such an entity can be 'stationary' is if the medium is moving in the opposite direction at the same speed as the soliton. You also introduced vortices. Vortex phenomena are different in that they can stand still. You can observe this in ordinary stream flow in a river bed where there are permanent eddies.

Thank you. So you now agree that a soliton cannot stand still as I originally said ?

Two books I found very very useful in the past and still contain useful stuff. They are good because they both contain much practical info and examples eg breadboarding interface circuits and so on. I don't know where you are in the world, but if you can get hold of an old Open University Hektor trainer you would be laughing. I built one and learned machine code and assembler on one. Also you can get some pretty sophistic 'logic trainer breadboards' second hand these days. These can be adapted for use with micros.

#This is true, but after a while I think going down the chain gets a bit silly. Did the man who worked in the factory have a metal buckle in his belt ? Did he wear a ring in his ear or have nails in hios boots? Did the canteen chef who made his dinner use a metal saucepan? And did he stir it with a metal spoon or a wooden one ? When the company boss watched the main news of the day on TV does his TV use a metal antenna ? Where does it end ?

I agree but then lithium cells are not necessarily the way forward. A shortsighted view. Answer both : Look at this heavy excavator powered by a hydrogen fuel cell. Zero CO2 Test post Edit posting system appears to be working for me.

That might be a good measure for a single ageing process I remember seeing a Building Research project that had been going on for about 30 years where they were testing drainpipes by constantly trickling dilute vinegar over them. But it has already been noted here that there are multiple ageing processes in CDs. One of which is not susceptible to such a speed up technique. This is what partly killed a good friend of mine at University. That is all plastics are subject to creep.

Good question +1 I haven't seen these but I do have some original Philips gold archival recordable CDs going strong. I bought these in the early 1990s

One more, This is not a textbook but a penguin paperback sized book that is a good read, if you like, as I do, following how a theory was arrived at, as presented by an expert who actually knows and understands that theory. The Perfect Theory Pedro Ferreira

Yes I have electricity and gas records, both financial and supply units, going back to 1987 when we moved into this house. Years vary and it is easy to pick out the hard winters plotting annual figures year by year. Averages are also good for other purposes. Better for comparison with other situations (eg I don't think Area54 has access to mains gas and LPG offers different performance figures). Utilities like setting up 'deals' and 'packages' and 'policy' - which can help them avoid (some) obligations under the UK Gas and Electricity supply Acts. This is why I have never sought or agreed to a change of terms under the original supply orders with the original supply organisations. The Acts in force at the time were binding on the original suppliers and their successors in title. Yes one of the upgrades to the central heating radiatior system was to split the heating into 2 zones. In my case upstairs and downstairs. These zones can be programmed to come on at different times and different temperatures and fall back to different temperatures when not in use. This part of the system has worked very well indeed. Yes, many factors are involved. The efficiency of the boiler varies with the humidity (and slightly the temperature) of the air, its own calorific value (which varies from time to time and the gas company has to publish in the bill), its state of internal cleanliness and of course as you say some of the heat necessarily is taken carrying away the exhaust gases and water vapour. Some of this is recovered as heat storage in the masonry of the chimney stack.

I feel sure that we have discussed DVD radiation protection before in other threads. @gamer87 I hope you will not take this the wrong way since you are right to worry about your DVD's When someone's post count gets to a certain level here, they are often 'awarded' a special category. So I nominate you for the special category of 'superworrier'. I used to be associated with an avant garde video production company that lost whole boxes of recordable DVD archives due to ageing. It can and does happen, and as iI noted some brands of media are better/worse than others. The watchphrase in the digital world is, as always, "it's backup, backup, backup darling." Two weeks ago I did just that with a DVD data archive disk dated 2005. I could hear the drive reading and re-reading and struggling to read the disk so I made a copy. You can tell when a disk is beginning to fail as it takes longer and longer to access and you can hear the multiple attempts to read. Did you know that The system contains a subroutine to read the disk several times until it obtains consistent data? This is also true of hard drives

Well it does penetrate a bit every time you take the lid off so keep them in smaller boxes so each one gets exposured less often. I see you have some shoe boxes. Theya re good since some are double walled.

I was talking to a second hand bookshop owner a couple of days ago. She told me that there has been a sharp rise in sales of academic books lately, particularly mathematical ones. She has been sending these all round the world during the Covid outbreak. Second hand is often a good way to keep the ridiculous prices of books in the UK down.

Oh yeah, right ! 🤣

Mechanically produced CDs and DVDs are unaffected by normal levels of sunlight. Ones you 'write' yourself (recordable and re-recordable) work on a different (chemical) principle which is light sensitive. Some brands are worse than others. So for these yes light protection is necessary. Cardboard is better than paper - the thicker the better.

My memory is not that long. 🙂 But neither Lovelace, nor Babbage were blacksmiths. Did you not understand my parable ?