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Recent content by AlbertG

  1. AlbertG

    Conditional Branching in Perl?

    To varying degrees of context/scope, this could be said of most queries posted throughout Eng-Tips. Thank you for sharing your expertise. Good day.
  2. AlbertG

    Conditional Branching in Perl?

    @LiteYear: Thanks for stopping by! Sorry to be away so long. Evaluating the $value variable was part of the problem. As a throwback from my OO days, I thought the variable would be reevaluated without direct placement. Thanks for the heads up. Here's one back! '$(pgrep some-process | wc)...
  3. AlbertG

    Conditional Branching in Perl?

    Addendum: Considering pgrep a little more, would something like this work just as well (or better): $value = '$(pgrep some-process > /dev/null)'; ???
  4. AlbertG

    Conditional Branching in Perl?

    Greetings! Well, I dug myself in over my head with a basic syntax debacle in Perl for my Linux box. Here's the code sample which I wish to fix: #!/usr/bin/perl $value = '$(pgrep some-process | wc) -gt 0'; TEST: if ($value) { sleep 2; zenity --warning --text="some-process is running."...
  5. AlbertG

    Basic Questions Concerning AC Power . . .

    @marks1080: Thanks for the post. I thought as much; but sometimes you question your own sanity in the simplest of things ;) Meanwhile, I'll stick to hunting this particular game with smaller caliber tools than the great "K"... Cheers!
  6. AlbertG

    Basic Questions Concerning AC Power . . .

    @davidbeach: You know, that's essentially what I was thinking: "All roads lead to Ohm." And, to (hopefully) answer your question, the load, supply, and circuit are completely stable and fixed. For the record, this whole thought problem is in the setting of standard 50/60Hz AC. Of particular...
  7. AlbertG

    Basic Questions Concerning AC Power . . .

    @waross: Thanks for stopping by! Good point. However, that particular aspect isn't really at issue in my little thought problem (it represents a small error on the whole). Again, the hypothetical load is a simple "black box" construct; representing a fixed, precharacterized RMS load value...
  8. AlbertG

    Basic Questions Concerning AC Power . . .

    Good day. I've had a tussle with this for a bit, and just now decided to break down and float it out for community assistance. In the scenario which is at issue, we have a "black box" load which may be essentially resistive or may be partially inductive; but has been precharacterized to...
  9. AlbertG

    nth Roots in Historic Mathcad 4.0?

    @rmix22: Functionally, that works; but there's no symbolic output. Trying to get a functional, standard nth root representation for the document... @Occupant: Sadly, no; that seems to have come into play much later than this old version-- Any other ideas? This seems like a rather queer...
  10. AlbertG

    nth Roots in Historic Mathcad 4.0?

    Greetings! Well, I dug out my old 4.0 floppies for a quick 5-year check (still good after after 21 years); and got bumbling with the program after a quick install from my trusty CD-R backup. This software is always great fun to work with; still a touchstone of convenience and power ;o) Well...
  11. AlbertG

    Static CR vs. Efficiency: Disappointing Otto Gains?

    From my OP: "Indeed, wouldn't looking at things from the standpoint of Carnot be a better first approach towards the overall goal in many instances?" To flesh this out a bit, what about lowering the cold-sink temperature of any given design's cycle via ATDC water vapor injection? After all, if...
  12. AlbertG

    Static CR vs. Efficiency: Disappointing Otto Gains?

    Hello folks! Had a niggle to finally look at the foundational formula concerning the relationship of CR to efficiency for the air-standard Otto Cycle, i.e. E = 1 - (1 / CR ^ (K - 1)), where K = 1.4 To my surprise, we see a relatively small increase for E across a significant span of CR values...
  13. AlbertG

    Solar heating of closed carbon fiber tube

    @benjachristensen: Having spent over 30 years in the Phoenix area, I can tell you the following: Virtually any sealed enclosure placed in the Summer sun in that climate IS a solar oven; regardless of color. If you have not experienced it yourself, it is hard to imagine... I would create a...
  14. AlbertG

    Basic Math Check for the Heating of 304 Stainless . . .

    @IRstuff: OK. So... We need to start with Q = mc(?T). Then, we should take the value of Q and factor in a set of losses to arrive at the steady-state heating energy available through the body. What would these factors be for a body such as this in still air at 25°C? Lastly, in...
  15. AlbertG

    Basic Math Check for the Heating of 304 Stainless . . .

    @IRstuff: OK. To recap, we need to start with the steady-state gray body radiation equation, q = ??(Th4 - Tc4) Ac instead of Q = mc(?T). Then, we should take the value of q and factor in a set of losses to arrive at the steady-state heating energy available through the body. That being...
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