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Recent content by mrelet

  1. mrelet

    What material is pencil eraser

    What material would be specified for erasing graphite marks, such as used in Staedtler-Mars erasers?
  2. mrelet

    Protect Metals submerged in swimming pool

    CoryPad, The non-chlorine treatment I found is ECOsmarte. They describe it as a "copper ionization technology" and "Oxidation is achieved when water passes through the titatnium electrode plate with a low voltage electrical current". I don't know, but the copper may be corrosive to the...
  3. mrelet

    Protect Metals submerged in swimming pool

    gr2vessels and CoryPads, The environment is heated (80 to 100 F)and treated water but does not otherwise see the normal pool loads, i.e. no people, few biologics. So, it probably does not require strong oxidizers to keep the water clear. As a test tank, it will be in use for 20 years or more...
  4. mrelet

    Protect Metals submerged in swimming pool

    The open tank (i.e swimming pool) will be stainless steel, frames will attach to inside of tank, polcarbonate sheets will attach to the frames. The frames will see about 100 lbs deadweight, and 100 lbs live load under test conditiotns that last less than 1 minute. The open tank and frames will...
  5. mrelet

    Protect Metals submerged in swimming pool

    I am going to build and submerge test hardware in a swimming pool. What type of stainless and what type of coating for alumium is recommended for long-term submersion? Should sacrificial anodes be considered?
  6. mrelet

    PVC cement bonding underwater in a swimming pool

    I need to find a product to permanently bond a pvc fitting to another while underwater in a swimming pool. Any ideas?
  7. mrelet

    Variable speed pump

    Artisi and BigInch: I stated up front the supply voltage is 230 V.
  8. mrelet

    Variable speed pump

    Artisi, your calculation might need work, as watts don't equal amps. Big Inch: it's variable frequency, so I start at lower power, right?
  9. mrelet

    Variable speed pump

    Anyone know where to find a 10 hp 230 V variable speed swimming pool pump?
  10. mrelet

    Infant shaking a crib

    Waross is on track: measure the frequency. Waross:"The answer may be out of the range of frequencies that an infant may reasonably be expected to generate". True. And I can measure it. But who will tell me what frequencies are within range?
  11. mrelet

    Infant shaking a crib

    geauxinspect is on tract to eliminate the problem I've presented which is can a baby/child be expected to find the resonance of a crib and exploit it (for his/her own pleasure). IRstuff points out that a crib rocker would be over-center unstable. I'm guessing their are no human factors types...
  12. mrelet

    Infant shaking a crib

    I'm not schooled in all the cases and there assigned causes. But parents have been suspected in some cases, for a variety of reasons. But I think you make the case that parental "rocking" is possible and of course "rocking" entails resonance. Wood shrinkage can cause loosening as the...
  13. mrelet

    Infant shaking a crib

    Well, so what I say about anecdotes? To be upfront, crib injuries related to hardware failure are pretty rare. But we treat rare with great respect w.r.t infants/children. I like your idea to review videos of kids in cribs. Thank you.
  14. mrelet

    Infant shaking a crib

    I'm a test engineer and am seeking advice on how effectively an infant could shake a crib to failure. Shaking loosens hardware like screws (over time) while impact can cause outright failure. It is known (and quite intuitive) that infants don't have alot of strength. Still, hardware loosens on...
  15. mrelet

    Typical or allowable air in pumped water system

    BigInch (Petroleum) Thanks for the very helpful threading. One more question: how do I build a bubble column?

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