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Everything posted by Externet

  1. Hi. I have somewhere among my spider webs, a gadget that I have never used, it is smaller than a pack of cigarettes, divided in two sections. One is a transmitter and the other a receiver. The transmitter half is meant to be attached to a kid (or a briefcase) and you keep the receiver in your pocket. If the distance between the halves exceeds ~5 metres, reception is lost and the alarm sounds. When not in use, one half attaches to the other turning both off. Miguel
  2. Hi. Why arcing ? All bodies will have the same charge polarity in order to be repelled. The rings would have to be suspended with strings, the cylinder vertical - Is that the way you envision? Miguel
  3. Hi. I have some idea of how they work, but never inspected one closely nor played with one. Question; what do you think would happen if bits and pieces of plastic are fed to it instead of sugar? Would it produce some "plastic wool" ? -Similar to fiberglass ?- (am not joking) Miguel
  4. Or the fuse in the current meter already let the smoke out in another previous goofing... Miguel
  5. Hi. The French had a plausible intention, but goofed big time with the development of the metric decimal system; not because of the metre, but because left the work unfinished and we are stuck to a senseless not decimal system in too many fields. Being the worst of all, the time measurement. A second should had been 1/100 of a minute; A minute should had been 1/100 of an hour; an hour should had been 1/10 of a day as example. The non decimal system is the one that is in need of a mission-impossible redefinition. And who came up with latitude and longitude not being decimal? Go spank those. Leave the metre alone and better think on fixing these really stupid non-decimal systems. Redefining the decimal metre based of a non-decimal second is a very wrong idea. If the British want to keep their liquid ounces, furlongs and grains, let them mess with their stuff as the urinal capacity of king such and such being the gallon standard.
  6. Hi Swansont. I said that just because someone may say the kinetic energy from the projectile dissipated into heat at the spring -or rubber- and will not move the car much because of the energy loss. As in another extreme example, the bumper with a layer of play-dough to avoid the bounce and drop after; someone can say the dough converted energy to heat in the deformation. JustStuit: Thanks for your calculations. If the projectile bounces back and still has some speed after the impact, isn't because did not deliver all of its kinetic energy ? and thus, the car will not move as much as in the case of the projectile that did not have energy left after the impact because it delivered all of it to the car ? Miguel
  7. Hi all. I do not see why the bounced projectile speed matters for the response, but if a figure is preferred as clarification, just say the projectile bounces back at 30% of the speed it had before impact. And some other detail if needed later; assume there is no thermal loss in the impact onto the springy or rubber bumper (the rubber -nor the projectile- will not heat up upon collision by deformation) Miguel
  8. Hi. A toy car receives the impact of a horizontally going projectile onto its solid, metallic, vertical rear bumper, and the projectile bounces back. The same toy, weighing the same as before with a springy or rubber bumper, receives the same projectile and it does not bounce backwards at all, just drops vertically after impact. Which case will push the car more distance because of the impact ? Miguel
  9. Hi. Post ALL the rules for the task up front. Miguel
  10. Hi. http://www.blacklightpower.com/ Miguel
  11. Two light sources S simoultaneously turned on; what is the relative speed (collision speed) of both light beams when propagation wavefronts meet midway ? S---------><----------S c-(-c)=? Miguel
  12. Hmmmm. But I will learn nothing downloading. And Spybot caused much trouble a year ago when I used it in my compfuser at work; will never get back there. I use AdAware ; McAfee Corporate and Yahoo popup blocker. But that is not the point. Am after the batch file. I will study how to make such batch, and try to set it to happen every monday. Miguel
  13. Hi all. OK, Bettina. Your response makes somewhat more sense to my dumbness. I do have anti-spy and anti-virus and all that which is not the subject here. And I will not get another firefox or whatever that will take me a year to learn. ...maybe And for all you, a batch file it may be a piece of cake, for me is hebrew, I do not know even what is a command line . So I open Wordpad as if I was to compose a letter; Write the steps I would do when deleting those files manually, in the same sequence, with proper syntax, save it into something you call 'startup' that I have no clue where it is... And this text named batch file would be something like: Open Windows explorer Go to Windows directory and open it, Select cookies folder and open it; select all files; delete; click yes if asked I want to send to the recycle can; when done, open temp internet folders; select all; delete all files; click yes if asked I want to send them to the recycle can; when done, empty recycle can; Display "Cleanup done, continue" for 2 seconds End of program At least you will get a laugh out of the above; but I told you, never done, and not much clues on how to . If an example can be posted here (as it is a piece of cake for you); I could taste some of the cake. Thanks for holding my hand, Miguel
  14. Hi. How to execute a set of commands automatically after finishes initialization (Win98 ; Win XP)? Getting into Windows explorer, I manually delete 'temporary internet files' and all 'cookies' from within their folders periodically, which is supposed to happen when the option to do it when closing the browser is selected under Internet 'tools' But it does not happen as expected, and besides cookies being kept in the cookies folder, they also hide in several 'internet temporary folders' along with more crap pumped by peddlers and spies of all sorts. To the colorguard of computers idiots (me), is not easy to implement such 'Startup?' set of actions. Can someone tell how to do it in simple terms and clear steps ? Miguel
  15. Hi. You may be under the wrong impression seeing one single cable that actually has many wire pairs in it, each pair handling only one communication path. If it is truly a single metal pair, can be digital communication, where the voices of multiple simoultaneous users are sliced in tiny portions, fed into the single wire pair (multiplexed) and at the other end, the slices sorted and put back together and properly re-routed (demultiplexing) Links between telephone central stations use the same multiplexing method on a single fiber optic, with thousands of rapidly sliced signals. Miguel
  16. Hi. Scuba tanks are rated ~3000 psi, ~80cuft.. If you fill one at full capacity, you have a good chance to rip your head off playing with its valve and pressure. Do not even dream of a garden hose! That is not a toy and can be lethal in wrong hands. Miguel Scuba diver
  17. Yes, Alienufo. As if you discover a reaction to reverse vulcanization to turn old tires back to rubber to make new tires. Selling that formula/method could yield figure$ you cannot imagine. Miguel
  18. What common materials/elements could be the ones used in this gadget? : http://dragonet.com/fhp/ Has 8 cells to yield 12V, and only anodes are consumed in operation.
  19. Hi . Does galvanic protection under seawater by the use of dissimilar potential metals create an electric field and electric current in the water? If yes, to what extent ? A mile apart chunks of zinc and iron, will there be an electric current between them ? Miguel
  20. Yes, for the same motion the stronger magnet will induce more current; but takes more force to push the strong magnet to achieve the same motion. Are you reading?
  21. Thanks gentlemen; that was very clear, simply better than some text books. The rectenna would be what am after, but in semiconductor style construction, perhaps using materials with the property that weak photons can knock their electrons off. Miguel:-)
  22. Hi. ..."Your kinetic energy is being changed by the magnetic field into electric is what you meant? energy. "... I would say that the stronger magnet takes more effort to pass it over the wire; then, the kinetic energy is different in every case. More force to move the stronger magnet, less for the other. The efficiency would be the ratio of the electrical energy generated and the kinetic energy requiered to move the magnet to produce such generation. In small experimenting driving magnets by hand, you cannot discern those minimal differences. You would need measuring instruments to show such. Just imagine a permanent magnet toy motor, -used as generator- how much torque needs to be spinned when electrically loaded. The same motor with no magnets in it (extreme case of weak magnets), will need much less torque to spin it with the same electrical load. Hope it helps, Miguel
  23. Thanks, gentlemen; am learning good from you. If all energy are photons, visible light range or radio range, the point of view can be changed from visible light spectrum to radio spectrum. As ..."IR has quite a low frequency and so it has low energy"... Focusing the center of attention to radiowaves (also photon EM energy) ; the IR spectrum has a MUCH higher frequency and higher energy than radio. Trying to express myself better: A plain microwave oven, rated say 1 Kw emits EM photons at 4 GHz. If its frequency is increased (towards IR) the energy emission would be greater (am not talking about its cooking abilities) as : "E = hf E is energy h is Planck's constant, simply put it's just a constant f is frequency" Then the new rephrasing would be... ¿How to manufacture a PN junction cell of some kind that will convert RF into an electric current and performing up to IR ? Is the explanation still the same -too low energy- ? If so, that 1Kw ! microwave oven is too little energy to recover any from its confined chamber by means of some sort of cell ? Thanks, Miguel
  24. Agreed, solar cells do not work with heat radiation. That is the point. Rephrasing... What would take to make a cell similar to solar but centered in the far IR ? -- "thermovoltaic" instead of photovoltaic -- It is not about sensors, as the ones used in infrared cameras and thermal imaging, those are fine for detection but not for generation. What does waaaay too low energy refers to ? The heat radiation to be collected or the electrovalence energyband something of the PN junction ? Miguel
  25. Thanks all for the explanations. I was interested in the radiation form of heat transmission only, it is difficult to understand how simple friction of two electrically inert bodies can radiate electromagnetic waves (heat).
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