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Recent content by gphatch

  1. gphatch

    Looking for reputable Neo vendors. Any recommendations?

    Yes indeed - only suppliers who have a license from one of the key players on the intellectual property side of things, are legally allowed to sell into the USA. Similar restrictions apply in Europe and Japan. You can read more about this at...
  2. gphatch

    Looking for reputable Neo vendors. Any recommendations?

    Currently there is very little production of Neo magnets in the USA, if any. These days, licensed Chinese Neo suppliers produce high quality materials that standup very well over time. Japanese Neo suppliers also produce high quality product. My own company, Dexter Magnetic Technologies, uses...
  3. gphatch

    How do you shut of a magnet?

    Perhaps there's more than just copper in the copper wire, if no current is flowing and it is attracted to the magnet? Gareth P. Hatch, Ph.D. Director of Technology Dexter Magnetic Technologies http://www.dextermag.com
  4. gphatch

    Magnetic resistance

    You might want to read up on Earnshaw's theorem, which, in the context of magnetics, can be paraphrased to state that there is no stable configuration of levitating permanent magnets - such systems always require a restriction in at least one axis to prevent one of the magnets in such a...
  5. gphatch

    Radially-oriented magnetization of Ring Magnets

    Daido Steel makes some very nice radially oriented Neo magnets. Gareth P. Hatch, Ph.D. Director of Technology Dexter Magnetic Technologies http://www.dextermag.com
  6. gphatch

    Residual magnetism

    Thank you kindly!
  7. gphatch

    Residual magnetism

    Can anyone give me an idea of the level of residual magnetism found in some pipes that have been worked repeatedly, due to the earth's magnetic field? Gareth P. Hatch, Ph.D. Director of Technology Dexter Magnetic Technologies http://www.dextermag.com
  8. gphatch

    electromagnetic field measurement

    Yes George - I agree that if the system can cope with a minimal air gap, that's a good approach to take. Generating large forces within smaller volumes though, is where permanent magnets just can't be beat, particularly if you put two magnets together side by side - the gradients become the...
  9. gphatch

    electromagnetic field measurement

    The force acting on a mobile entity, that responds to a magnetic field, is proportional to the product of the field magnitude and the gradient of that field, at that point in space. So to maximize the force, you need to maximize this product - the easiest way is to use a "reasonable" value for...
  10. gphatch

    R.H.P System:

    Any chance of providing this information in a non-ZIP format? I am prevented by company policy from opening unknown ZIP files. Gareth P. Hatch, Ph.D. Director of Technology Dexter Magnetic Technologies http://www.dextermag.com
  11. gphatch

    Help with very basic SQL queries

    Me again... how would I automate the modification to the Link table with the lowest nameid for each name [which you kindly showed me in post 2 above], using the first query you gave me, which shows which names have duplicates? I ask this becuase I just re-ran the COUNT query and I have over...
  12. gphatch

    Help with very basic SQL queries

    Yes - you describe the situation very well. The problem with the original data entry, is that the person was entering a whole list of names, in each Category. They did not really know if the same name appeared in a different or older Category - they just knew that it was in the Category they...
  13. gphatch

    Help with very basic SQL queries

    Thanks for the explanation. I think I'm still missing one small piece of the puzzle - are you suggesting that I should have multiple records in the Category table, which each have the same Category Name, but unique CategoryID and NameID values? E.g. 1 - History - Yes - 45 2 - History - Yes -...
  14. gphatch

    Help with very basic SQL queries

    Thank you so much for this assistance! I'll try doing this, this week. On your comment regarding the database design - I can see how your suggestion would work if a name was associated with only one Category - but since it could be associated with more than one Category, how would I accommodate...
  15. gphatch

    Modelling packages

    For a BEA solution, look at Lorentz [3D] and Magneto [2D] from IES. No time-consuming meshing - very quick results generation. Gareth P. Hatch, Ph.D. Director of Technology Dexter Magnetic Technologies http://www.dextermag.com
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