Recent content by Jeff Rosenbury

  1. J

    I Matter cutting by destabilising of atoms bonding

    Yes. One could for example replace the electrons with muons, changing field configuration thus disrupting crystal structure. That's a bit exotic since muons are rare. More practically one could use another stronger field to disrupt a weaker field. An example would be using the strong field...
  2. J

    Insights Scientific Inference and How We Come to Know Stuff - Comments

    It is fascinating to me that my favorite definition of energy (Noetherian energy) relies on the assumption of such regularities in the universe. This is so true, that to some extent modern scientific models are based on this underlying Lagrangian path. In other words, since the real (as in true)...
  3. J

    Insights Scientific Inference and How We Come to Know Stuff - Comments

    Even in pure math the answer isn't clear to me. Gödel proved a disturbing theorem (the incompleteness theorem) which approaches this point tangentially. It is possible even some theorems in math depend on viewpoint, thus sense data. But since the incompleteness theorem doesn't apply directly...
  4. J

    Insights Scientific Inference and How We Come to Know Stuff - Comments

    Kant (1724-1804) argued that a priori knowledge exists. That is that some things can be known before [without] reference to our senses. Hume (1711-1776) argued that only a posteriori knowledge exists; knowledge is gained exclusively after perception through senses. Hume promoted a more pure...
  5. J

    Insights Scientific Inference and How We Come to Know Stuff - Comments

    Dr. Courtney: Whether students agreeing with the consensus is a good measure depends on one's view of the purpose of education. Early 20th century education reformers like Dewy saw the purpose of education as the promotion of political unity. It's not clear to me that has changed. As...
  6. J

    How can a function be analytic in the s-plane

    Not all differential equations have analytic solutions. When these problems need to be solved they are sometimes solved either numerically or stochastically. To solve numerically, use a computer to solve small bits as if they were differential elements. Make sure to run an error analysis. An...
  7. J

    A question about electromagnetic induction

    Other answers are good. But for the basic, underlying cause? We don't know. The universe acts the way it acts. We observe that action and create models of how it acts based on experimentation. But there's always another "why" somewhere. As for why Maxwell's equations work the way they do...
  8. J

    Everything About RAM: All You Need to Know

    Say, "more than they have." I'm sure all PF regulars are worth far more than they get paid. :oldwink:
  9. J

    B How can we get clothes out of a vacuum chamber without condensing water on them?

    I've seen this done with nylon hose (panty hose) as a filter. It still produces lots of dust, but perhaps not dangerous levels. It also adds lots of humidity, but so does hanging clothes on a drying rack (my current solution).
  10. J

    B How can we get clothes out of a vacuum chamber without condensing water on them?

    My understanding of partial pressures is that the amount of water vapor is nearly independent of the amount of other gasses. So raising the temperature raises the amount of water vapor as well as providing the heat of vaporization. Reducing pressure only forces boiling when it drops below the...
  11. J

    Upgrade Your Motorbike with LED Accent Lights: A Correct Circuit and Relay Guide

    Relays can be tricky. Read the data sheet and app notes carefully.
  12. J

    Maximum voltage from blowing through small turbine?

    Try not to keep any extra oxygen around. The stuff is flamable-ish. Things that don't normally burn might spontaneously ignite/explode under pure oxygen.
  13. J

    Can LED bulbs be safely used in motorcycles without additional modifications?

    On second thought, I have to agree with OmCheeto here. :blushing: You do not have the required background to be making this modification. The parts need to be selected with the right values. Additional parts may be needed (such as a blocking capacitor for the flyback if a flyback is needed). And...
  14. J

    Can LED bulbs be safely used in motorcycles without additional modifications?

    Option C. Put a current limiting resistor in series with the LED. At least if this is an indicator light. If it's a brighter light (headlamp, tail light, etc.) you might want to consider more energy efficient options. You might also need a flyback diode (option A) if the line is noisy from...
  15. J

    B How can we get clothes out of a vacuum chamber without condensing water on them?

    Always bringing reality to the discussion. It's not enough to rain with my heater/condenser, you have to rain on my parade as well. :bow: Good job. I can think of ways around the problem, but they go beyond the practical. At best, I think would be a low(er) pressure intercooler to pre-dry the...
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