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About Externet

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  • Location
    Mideast U.S.
  • Interests
    Old Cadillacs, scuba.
  • College Major/Degree
    Electronics engineer, audio recording engineer.
  • Favorite Area of Science
  • Biography
    Plain old fart tells it all.
  • Occupation
    Retired from electronics and shrimp farming.

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  1. History Section

    Perhaps it is not science ?
  2. Vortex bladeless 'turbine' ...

    Do you see any promising future for these vortex bladeless electricity generators ? Production costs against power generation capability ? How solid technology can this become ? ----> https://vortexbladeless.com/technology-design/ (Please move to 'Engineering' if better deserved)
  3. Dual glass pane windows...

    As solar radiation crosses a single glass window, its warming of the room is kept as the heat has 'difficulty' in exiting again trough the glass towards the exterior. In a dual pane window, after passing the external glass, there is little sun radiation to further cross the internal glass pane, warming the window. Does it mean that a room with two glass pane window will allow less solar penetration to warm a room than a single glass window ? (but will insulate better against internally generated heating system losses ? )
  4. More on gyroscopic behaviours

    Like the flywheel being attached to the central shaft ?
  5. ~40mA as reported is usually twice the maximum rated current for a "tiny" LED as described. If still emitting light, we do not know. The missing resistor value that needed when first connected depends on its color (chemistry). Example : If it is a red LED, and the battery is at 2.8V state Sustract the red Vf : 2.8V - 1.8Vf =1.0V For a 10mA recommended current by LED manufacturer, 1.0V / 0.01A = 100 Ohms series resistor.
  6. Finding due South

    The shade of a plumb cord will trace a perfect north-south line at the time a chart shows sun azimuth being 180 degrees for your coordinates, or 12:00N sideral (astral) time; or when sun elevation is at maximum.
  7. A LED proper connection to two cells in series should include a resistor also in series to limit the current. Lacking current limitation, the thermal properties of the LED can increase the current demand as the LED warms up with elapsed time on. The batteries can also change their internal resistance with temperature with the elapsed time on. As the cells deplete, the current should decrease as the battery voltage gets lower in time. The time can be many hours, depending on the capability and charge state of the battery. Unequal state of charge for each cell can also cause unusual readings.
  8. Finding due South

    Hi. Use a chart for sun position at your coordinates. It tells you at what exact sidereal time/date, sun azimuth is at 180 degrees. Hope for sunny sky. I did it to orient a satellite dish antenna and worked very well. ----> https://aa.usno.navy.mil/data/docs/AltAz.php There is other charts/calculators to choose.
  9. Check if this older thread contributes with some extra information: ---->
  10. How Resistance Change Depending On Temperature

    Consider there is PTC -positive temperature coefficient- and NTC -negative temperature coefficient- devices/probes
  11. Is it improper to add temperature and 'verticality' (balance) senses to the normally listed hearing, tact, taste, vision, smell ? An eighth could be the common sense, the least common of senses... I can directionally detect nearby hot spots with cheeks, hot/cold ingested foods; body position in darkness/bed, by inner ear or guts.
  12. How Engine Braking Works

    The engine acts as a compressor with blocked inlet/outlet. And it is engine braking, not breaking... Edited- added ----> https://en.wikipedia.org/wiki/Engine_braking
  13. Plastic waste, cruise ships & impacts on the Ocean?

    Many years ago, ocean liners dumped their own refuse to sea. Later, was legislated for international waters only. Years later, all ships must bring to ports their garbage. U.S. has its legislation ----> https://www.gc.noaa.gov/documents/gcil_crs_oda.pdf Go to 'Laws and treaties' at ----> https://en.wikipedia.org/wiki/Marine_debris
  14. Hi. These gadgets for reading pH; how they read on same soil samples with different contents of moisture ? Is there any compensating to ignore changes of conductivity by soil wetness ? How dry or wet can soil be for accurate reading ?
  15. First flight completely powered by ion drive.

    The airplane works on 'electric wind' from ion emission. The radiometer is onto something else.