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Externet

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Everything posted by Externet

  1. The aerofoil profile determines the 'rotatability'; the blade thickness is made thicker near the hub for structural stiffness; the lenght of blades determines the swept 'disc' area which is proportional to the power capture capability; the narrowness of the blades allow some change in the wind speed while passing trough the swept disc yielding more uniform power extraction. If they were too narrow, wind would not slow down enough to get optimal power out of it; if made too wide wind slows down too much and diverts toward outside of the swept 'disc' yielding less power. Economics, manufacturing , transporting, assembly and even aesthetics have a role in the shape of blades. A wide tip blade as you mention would turn with a much greater force when hit by wind, but when gets to speed, the extractable power becomes less. -As far as I understand the thing...
  2. Hi. A piston compressor can, but Would a scroll compressor work as an air motor if fed by compressed air ? Would it turn accordingly to its air supply? They work hot as any compressor and their machined tolerances would be not ideal if they will run very cold because of the expansion. What considerations/re-machining would be convenient to implement, or what would be detrimental to its performance/efficiency if not re-machined ? Would internal heating from friction be 'helpful' to efficiency as it would aid into the expansion?
  3. Reading now... 3001: The final odissey - By Arthur Clarke.
  4. Named...? By the manufacturer, usually the company that manufactures, plus a reognized industry family, a sequential number from the development department, or the same number from another manufacturer if intended to be a replacement, and other markings as for material the enclosure is made of. Example : MC4053PSJT. can be: M= Motorola C= CMOS or complementary metal oxide semiconductor, 40 = a family of CMOS 53= a sequential from the first manufacturer or mandated by an electronics association that implies a certain function P= plastic body S= surface mount J= Gull wing leads T = dimensions of body. Additionally, other markings shown as 9312 S mean manufactured in 1993 - twelvth week, at the Singapore plant. Or NE555CN For National semiconductor, Internal code, equivalent number to original IC, ceramic body, trough hole mount... From the user point of view, as to name a designator on boards or schematics; it is from the beginning that integrated circuits are named Uxx, or ICxx; being xx an arbitrary number that correlates a sequence on parts list or location on a schematic or board. Transformers T; capacitors C, Inductol L; resistors R; crystals X; P plug; J jack; etc. are standardized nomenclature.
  5. Thanks. I believe the roman government documented the crucifixion of Jesus; As the majority of apostles were later crucified, I would had thought there were some governamental records of 'judgements' for their activities. I once visited the Mamertine prison that held Paul and Peter, but never thought of asking the reasons why they were captive by Rome. Edited: added ---> I believe the apostle who went to India was Thomas. And killed there.
  6. As the bible tells some activities of Jesus and many other people along the years, I would like to know some documented activities from the apostles; as seems they did not write about themselves or other apostles. Any help there ?
  7. There is good examples and experiments in the net; here you have a few : http://www.winstonbrill.com/bril001/html/article_index/articles/1-50/article12_body.html http://www.packratworkshop.com/hotwater7.htm www.imagesco.com/nitinol/files/heatengine2.pdf Think about them and develop your own.
  8. Overcivilized
  9. What component of the engine would you make with nitinol ? Or do you mean to design an engine based on nitinol properties? There is some gadgets and science experimentation kits using nitinol, and probable one of the kits includes a toy car. I believe nitinol was found by high tech companies analyzing the fuselage material of a recovered flying disc; but was not part of its propulsion.
  10. To compress one litre of refrigerant gas, from atmospheric pressure to say 100 psi; takes X amount of energy To compress one litre of air, from atmospheric pressure to say 100 psi; does it take the same amount of energy ? In the examples above, none the gases will become liquified at a condenser; just cooled to ambient temperature. If both gases take the same amount of energy for the task; why air is not a good to use as refrigerant gas yielding a poor coheficient of performance COP ? If both gases take different amount of energy for the task; is the one that will take less energy the one that will be a poorer refrigerant ? Would a good refrigerant gas be good only if in the compression/cooling/expanding process the change of state -gas to liquid to gas- is achieved ? If there is no change of state; are the COPs equal for all gases ?
  11. Radio interference can enter your compfuser by the power mains or by the air as waves. Tri a 0.001 microfarad capacitor connected in parallel to each speaker If that does not cure it, the compfuser internal circuitry is picking the interference somewhere. Ask the neighbor to confirm the health of his installation; as cables, connections, grounding, matching, standing waves presence.
  12. Hi. Looking for the glossiest finish spray paint can; buying several brands and trying/comparing would be the only way to judge them; but there is a place that fills spray cans with the paint of customer's choice. What compound determines gloss, in order to ask for extra of that when filling ? -No clear coats later-
  13. America is not a country. It is a continent. I would choose New Zealand.
  14. Avoid hangovers... Stay drunk !
  15. Hi all. Most of us retain in our memory about 1000 songs since childhood, where their exact notes, durations, sequences, instruments, lyrics, tempo, voice, tones, cadence, pitch, chords, echoes, performer, and even more details pertaining particularities of each tune. To the point that any tiny deviation in one single detail as a note, instrument change, microphone positioning as in a live or different recording is immediately noticeable. Even we can anticipate passages coming next. How can the brain keep so much fine detail saved ? Any theories about it ? And what would be the Terabytes equivalent of such recognizable detail in a single tune multiplied by the number of tunes remembered ? Movies, in change, seem to be much less remembered in detail for their scenes, dialogs, events... We can remember all that detail vividly and automatically on a perhaps irrelevant need as music; but it is much harder to retrieve/remember the relevant instruction received along the years studying and learning, it just fades away in time... How come ?
  16. Hi. Does anyone know a manufacturer of 1 to 2 mm thick flat vinyl 4' x 8' sheeting ? Sort of same type of material homes use as 'siding' ? (Not tyvek products) Seen signs printed on such material at Lowe's stores but they do not carry the product. Somehow the net did not show much, or I did not search the proper terms. Thanks.
  17. Should not be a problem Not at all. Fill any bottle fully with non-compressible parts of whatever and all will survive 681psi.
  18. Think of a light dimmer... turning the knob varies a tiny amount of current fed to a device called triac, similar to a transistor, it allows the mains power to flow accordingly. The triac conducts the household electricity more or less according to that small amount of current driving it. If instead of a potentiometer on a knob, you use an audio amplifier and its output levels variation is properly fed to control that triac, the result is electrical power modulated by sound intensity. The gadget to modulate lights to music is just a little more elaborated than a plain dimmer.
  19. Hi all. Does anyone knows what is this pictured item ? It is about 7 to 8 inches, appears to be iron. Thanks
  20. Not a single brick here, but some of the flat pack part; its design is to drool. Get your beach size towel as a bib now : ---> http://dornob.com/open-house-modern-fold-out-mobile-home-design/
  21. Much cheaper would be to build condom factories all over those places, for free distribution...
  22. About a mile from my place ocurred that San Bruno underground gas pipe explosion, got me wondering... As it left a crater and ejected a pipe section, the explosion was underground... I think. How the needed air/oxygen for an explosion to occur got into the packed pipe sorroundings? If the pipe was leaking before the event, less chance for air to get underground, as would be flushed out by the outgoing gas. I think. The fire in the gas filled pipe did not propagate inside the pipe further lenghtwise to other served neighborhoods, as there was no oxygen. The spark... on highly doubtful conditions, the spark had to happen underground... perhaps metal-to-metal grinding at the moment of rupture. Any guesses until experts say something ?
  23. Hi. In some other forum, a beginner asked how to run a domestic clothes dryer from batteries to save in electrical power , and responses were of course, to discourage such by multiple solid reasons. I suggested as alternative to make a 'closet' with the clothes hanging and force fan-air flow, no heat added. It would take much longer time, but... Would that electric fanning take much less energy for a much longer time ending in a not-worth-it alternative than a several kilowatts for only a couple of hours domestic clothes dryer ? In other words, would indoor clothes drying need to use the same amount of energy no matter what the method ? I do not think so, but would like comments. The extreme is just leaving clothes hanging for a week? indoors, they will dry anyway for $0
  24. The battery itself has no power enough for that bulb. Try a LED instead, it glows with a few milliamperes. The amount of wet surface area on the electrodes is too small, better use foil. If different metals as electrodes, could be reversed polarity fighting against the battery potential.
  25. Thanks, John. Would time help in the migration ? If ions happen to partially migrate under the electric field, is their (ions) interactive repulsion because they have the same charge polarity another limiting factor for greater segregation ? Ions of same charge do not 'like' to be piled up together.
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