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Externet

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Everything posted by Externet

  1. Perhaps this could be in general physics, but here I go... What is the voltage generated using Aluminium and copper Carbon and magnesium Aluminium and magnesium Copper and magnesium as electrodes in 3.4% ClNa ? Where is a table that gives the values that its differential potentials determines the voltage generated ? -if that is how I remember it works- Miguel Merged post follows: Consecutive posts mergedNever mind... found it: http://www.corrosionsource.com/handbook/galv_series.htm
  2. Hi. Similar but not exact, yes. No problem, it was properly responded. Thanks. Opened another thread due the response rationale; poor retention and wicking effect of nylon, availability of material was getting complex, and decided to make things simple to obtain, plus a change in hardware from exposure to sunlight into shade. Miguel
  3. I learned in elementary school 1 Kilogram equals 1 litre or 1Kcc of water; 1 gram equals 1 CC of water. Merged post follows: Consecutive posts merged The metre was defined first. Measured the distance from a pole to equator, divided by 10 million. They got pretty close with the technology available then. Derived from it, the litre (0.1m x 0.1m x 0.1m) and the ton (1m x 1m x 1m of water). Speed derives from it, also force, acceleration and many others. The definition of time is were the french reaaaaally goofed big time; and it is way too late to make a unit now. Temperature remains a rare animal. Other major goofs are adopting anything not decimal. Longitude and latitude, degrees on a circle, twelve months... It is all messed up. But we have to live with it. At least is not worse than the volume of the urinals of king and queen whatever of England for the imperial and the other gallon, and the size of the thumb for an inch. And a pound that abbreviates lb instead of pd?. What a joke. Miguel
  4. A white towel or a black towel, both equally soaked and under same test conditions in the shade ?
  5. If a heat source cannot be concentrated to a hotter temperature spot, S M M M M M M Radiation from the sun S above heats and illuminates this target ---> + to -say 50C- with the intensity of one sun. The radiation from the sun S hits mirrors "M" at left aligned to all reflect onto target + to a total of 7 suns intensity. If the mirrors were covered with an infrared pass filter that blocks visible light, the target + will not be hotter than 50C ? Again; If a heat source cannot be concentrated to a hotter temperature spot, Does it mean the heat at the top of this tower comes only from the concentrated reflection of visible light and the heat part of the sun radiation is not a factor ? ----> http://www.nickelinstitute.org/multimedia/magazine/2008/December_2008/Solar/solar1-650.jpg Miguel
  6. OK. Let's say that infrared lenses do exist. Where in the spectrum heat falls, am unsure if those lenses be functional: http://www.3dlens.com/infraredfresnellens.htm http://www.thorlabs.com/navigation.cfm?Guide_ID=132&gclid=CMbxi9fwr5sCFSIuagodb1nWCg A pot boiling water on your stove top, 20cm size, 100 C. If an infrared lens is placed in front of the pot, its 'projected' infrared focused point to a 1 cm spot would never be over 100 C, as I understand from what has been explained. Miguel
  7. Thanks. Yes, it is to happen at atmospheric pressure, for distillation; and as suggested, 'flash evaporation' makes better sense than 'flash distillation' even when that is usually named when performed at partial vacuum. Miguel Merged post follows: Consecutive posts merged The instantaneous steaming is because pouring the water slowly seems the preferred method for a small size vessel that is permanently at 600 C + and evaporation is wanted for distillation. The agitation from boiling causes an undesirable spill effect in this small vessel. The excess high-heat at the vessel is a waste by-product of a combustion process, trying to be used in the needed distillation instead of dedicating an additional heat source. The vessel is to be periodically scraped to remove deposits left from the evaporation. Miguel
  8. L1 = L0(1 + αL(T2 − T1)) The formula to find how long will be a stainless steel rod , alpha=17.3 from initial length 700mm after delta t = 600 C Yields a senseless number. Where am I goofing?
  9. Hello. Slowly pouring water onto a very, very hot vessel so there is instant steam production; how is that method called ? -It is not 'flash' distillation- Miguel
  10. Venturing to speculate, a compressor needs valves to isolate the compressed gas from the rarified gas when exposed to a pulsating wavefront. A piezoelectric transducer has a deflection measured in microns; and cannot see how such microvalve could be built to react at over 20KHz with such a tiny gap. The amplitude of wavefronts is also equally small. Lower audio frequencies -say 60Hz- do create more convenient compression amplitudes and standing waves in a calibrated length acoustical port duct. Tapping the compressor outlet at that location on the duct, could raise pressure, but not much flow unless an inlet is provided at the standing wave antinode. Search for acoustical wave compressor, I read something about it a long ago. Miguel Edited: added----> Fig 10 at patent 5167124 is supposed to be in ultrasonics. I did not guess too bad!
  11. One soaked black towel, made of 100% cotton in same test conditions as another black 'towel' made of 100% nylon; under the sun... Which one would evaporate/dry more rapidly ? -Or is there any other better material choice with the same texture- Miguel
  12. More Amperes at less Volts are achieved with less turns of thicker wire. The rpm and magnetic field strenght are both directly proportional to the multiplication of Amperes and Volts; that is, Watts. More speed or more magnetic field will raise both figures = more Watts Miguel
  13. Let me try another wording/example. If a person is at a focus of an elliptical mirror; would the body heat reach the other focus and warm up a little object placed there to same or more than 37 C ? As a lens and light. The light gets brighter at the focal point of a lens because all rays merge there. If radiated heat behaves as radiated light but in another wavelenght, how to harness/route/handle that heat radiation into a 'spot' which will get hotter than the heat source? Miguel
  14. As light can be focused to a small area with the use of a lens, how could heat -say from a household radiator- be concentrated into a smaller area ? As to focusing invisible heat from a large source to raise temperature of a smaller body- Miguel
  15. Has anyone related affective times in life with more vivid dreaming, like pleasant dreaming in color and with details remembered long after ? And in periods of not feeling love for someone, to diminish, or dreams ceasing at all ? -Not related to make sense or not about the dream, nor to ease of falling asleep-
  16. Burr-Brown also makes it, and their application note is here: http://www.eetasia.com/datasheet/pbDSDownload.do?datasheetID=1000045781&partNumber=OPA541&pdfFilePath=http://www.ti.com/lit/gpn/opa541 Good luck, Miguel
  17. Surface mount tiny leds in small hobby quantities, are very hard to find unless you canibalize defunct equipment. In large quantities, there is hundreds of providers looking for sales, and most have a minimum order. This place may be the most convenient for you : http://parts.digikey.com/1/parts-kws/smd-led
  18. That is the one in my link above, readable on-line. Published repeated times every few years and the last one seems to be in 1984, but I do not know if the last edition contains newer material. Will find out soon. Miguel
  19. Hi. It does not seem to be any of those in the links. I saw such USA printed book overseas around 1980 and had 'modern' formulas and detailed processes to manufacture real products. Still have not located it, but not searched thoroughly lately. edited: added Jene: Try yourself with your techniques and clues you remember on scirus.com and ojose.com and come back with findings. Forget about google and take your time fine-tuning the search. Miguel (original poster) Merged post follows: Consecutive posts mergedThis seems to be the oldest edition (1914) of the book, readable on line - thanks, ojose search engine! - : http://www.archive.org/stream/henleystwentieth00hiscrich#page/n7/mode/2up And I think I located the 1984 edition, going for it. Hope includes 'modern' stuff in it. Its ISBN number is 0877810281 Miguel
  20. Hi. Trying to find out if by mixing a few not-fancy compounds, a thick ink can be made, like the ones used in ballpoint pens. Remember those high school experiments that produce colored solutions... Can they be made in a viscous form? How are ballpoint inks made?
  21. You do need those two 1000 ohms resistors in the circuit. Miguel
  22. It should. Come back with results. Some transistors have the habit of staying on when a 'pull down' resistor is omitted, but go ahead. Miguel
  23. A battery powered cooling device can be as simple as a propeller promoting faster evaporation from the towel surface. A Peltier effect cooling device would also work, if its heating half is also able to cool itself by wind of fan.
  24. A towel presents a very porous and large surface that promotes its moisture to evaporate faster as there is large area of water contacting the air. When water evaporates absorbs heat. 540 calories each gram. That cools the wet towel, and you in contact with it. It is nothing out of the ordinary and well known effect. When you want to evaporate water, you heat it up with a flame, sun rays,... or your warm neck. If you want the same in turbo mode, wet the towel in alcohol. http://en.wikipedia.org/wiki/Evaporative_cooler Miguel
  25. Hi. The first schematic is a theoric analogy for the AND gate. The lamp, relay or load would connect between the 'out' node and the ground (bottom) The positive of your battery goes at the top and its negative to the ground. The second schematic is very wrong. Erase the short vertical line portion above the top transistor that joins the red and black curved wires. The leftmost vertical line is very wrong. Puts a direct short circuit connection between the battery terminals. At least erase the portion from the "0V" up to the lower B switch The bulb won't shine bright as has a 680 ohm resistor in series with it. A led instead of the light bulb would work much better. Observe polarity if you replace it. Anode to the top (+) , cathode to the upper transistor collector. The top horizontal line is where you connect your 6V battery (+); the bottom horizontal line is for the battery (-) Ignore or erase the rightmost extension of the bottom line, (from the 680 ohm resistor towards the right.) Miguel
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