Mostly OT: meeting with some designers of cardiac implants



    Got it. Thanks!

    The PDF format should be acceptable on the dropbox, if you want it to be up forever. Powerpoint, Word, and a bunch of other things with macro languages are not trusted for good reason.
    Thanks,         DoN.
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We get presentations all the time that are about that large, and it's always because of lots of high resolution photos, many of which are scaled on the slides to the point where all that resolution is mostly wasted. If you have a couple of 6 Megapixels photos on each page, it adds up fast. The military is very big on slides with lots of little images of tanks & planes & the like. Each postage stamp sized picture is taken with a 10 megapixel camera, and then shrunk down for the slides. A high resolution color laser printer will spend an hour printing it out in all its tiny detail, but if folks are only going to look at it on a computer screen it's largely for naught.
In theory, your photos don't need any more resolution than the image size at the highest rez display device folks will use to view it. It's a real pain in the neck to try to rescale all your photos manually, but I think the latest version of PowerPoint may be able to re-scale an entire presentation's photos so that you aren't wasting any pixels for the size of the slides on a regular computer screen.
Another option would be to print it to a PDF. I know Acrobat has an optimizer that can shrink things down a lot, basically using the same idea.
Doug White
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On Sun, 08 Mar 2009 22:40:48 GMT, snipped-for-privacy@alum.mit.edu (Doug White) wrote:

That worked, shrunk it down to 8 megs.
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Don,
Great work & a great write-up! I've occasionally gotten involved in what I call "rabid research", where the answer to a question just isn't out there, and requires a home grown science project. Yours is the most wonderfully extreme and successful story of all. My hats off to you.
Doug White
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I have to say congrats to you for doing a splendid job of applied research. And I have to say congrats to them for overcoming the usual NIH syndrome and inviting you to come in and present to them.
As for the getting the project done in 5 days: It's amazing what focus and no distractions can do for a project. I've had students do industry projects, had the Engineering Manager tell me "we should have you do all our prototype development. You can do it much faster and better than we can" That was for a project where the goal was 65% reduction in mfg costs, my students only got 60% of the cost out but the field reliability went up by 5 to 10 times.
But maybe you DO want to take on a project now and again?? A few extra bucks and a few patent apps might make things interesting!! :)
Don Foreman wrote:

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    --Sometimes someone on this group spins gold. Thanks for that! :-)
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"Steamboat Ed" Haas : Politics is a sinkhole for
Hacking the Trailing Edge! : people without hobbies...
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On Sat, 07 Mar 2009 01:24:34 -0600, Don Foreman wrote:

Oh you bastard.
"Butt welding needles".
Now I have to save up for a TIG machine, to make _proper_ landing gear for scale model airplanes.
Will any old TIG machine do?
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wrote:

I would think so. Mine is an old Miller Dialarc HF. But you can also buttweld needles very nicely with a Smith Little Torch. http://www.littletorch.com /
I even weld thermocouples from 24 gage wire with the Little Torch.
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Any TIG machine will not do. Before you buy, look at the minimum current. The less expensive machines have a minimum of about 12 amps. Too much for needles.
Dan
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On Sat, 07 Mar 2009 23:45:21 -0600, Don Foreman wrote:

I'll have to try the little torch -- I have one of those.
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Don Foreman wrote:

Sounds like it. Isn't it great when you get to talk with the guys who know their stuff?
Kevin Gallimore
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On Sat, 07 Mar 2009 01:24:34 -0600, Don Foreman
<snip>

<snip> -------------- Wonderful outcome and thanks for the "rest of the story" report back to the group.
Unka' George [George McDuffee] ------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?
Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).
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F. George McDuffee wrote:

Maybe Paul Harvey is still around. :-) ...lew...
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I'm duly impressed. I went back through the archives, made up this set of excerpts from Don's postings. Makes a very interesting read.
Did I say I was really impressed?
Excerpts from Don: (Make sure you look at the dates AND times!)
1/6/09
Does an implanted cardiac defibrillator preclude use of MIG and TIG, particularly TIG with HF?
My limited web research indicates not but I'd like to see more data. Here's what I've found thus far:
http://www.journals.elsevierhealth.com/periodicals/jac/article/PII0735109796001477/abstract http://www3.interscience.wiley.com/journal/119977904/abstract?CRETRY=1&SRETRY=0
1/13/09 12:40 AM
Summary: not lookin' promising.
I've had contact with some good people: a senior fellow engineer at a major ICD mfr, a former employee (engineer) of a major ICD mfr and friend of many years, my wife's niece who is a former cardiac nurse of 30+ years experience, and helpful others.
Findings:
There are reported cases of weldors returning to work with ICD's but the reports are sketchy on details. One report mentions a minimum distance of 24" between weldor and cables, work and torch. That ain't how I weld: my face is right in there with 2 diopter lenses in my mask.
The experience of having a defib misfire has been variously described as being hit by lightning and being kicked in the chest by a mule. I'd rather skip that experience. Welding is fun, being kicked in the chest by a mule very probably isn't.
I can't seem to get data on acceptable field strengths (E-field and H or B field) that won't cause an ICD to malfunction. I opined that this is probably because the goddamned lawyers make this data highly proprietary. That was confirmed by the engineer (and friend) formerly employed by a major mfr. Goddamned lawyers.
So I'm about SOL here, not being up for a mule kick in chest while experimenting, candyass that I am.
Helluvit is that I have no friends who can do TIG and MIG, though Karl Townsend's son "the kid" may be a savior. Neither of my sons are at all interested. One daughter is, and she's done some nice work with MIG but she lives in Brooklyn NY so she's not exactly local.
Mar, bless her hawrt, has volunteered that she might do a Vo-Tech course in TIG and MIG. She'd be a natural, that based on her precision quilting and prowess with handgun, both hand-eyes coordination activites. TBD how that goes, but whatta teammate for even considering it, eh? Hey, she severely aced ground school for pilot licence for previous hub in the bad old days. Highest score they'd ever seen if I recall correctly. What a fool he was for doing her wrong, what good luck for me and eventually us. Goin' on 30 years now and it just keeps getting better.
Most folks are quite happily "weld free" in their dotages, right? Still, it's a bit of a lump to be prohibited from practicing a skill and activity I've enjoyed developing over decades and frequently find useful in my shop. Oh shit oh dear, poor me.
I intend to wallow in this for a while, fuck you if you can't take a joke. I'm not happy about this, but it's no secret that gettin' old ain't for sissies.
1/13/09 11:20 PM
Lots of new data today. Tons. I actually did get some real EMI specifications, thanks to the good folks at Boston Scientific. The key spec is probably 60Hz B field at 1 gauss (0.1 millitesla). Finally, something I can get some traction with. I need to make some measurements, but I think 1 gauss might not be a problem if I dress the cables well and keep the current below 200 amps which would not be an issue at all. I could probably keep it below 125 amps without giving up much. Gotta build a little gauss sensor. I'll do that tomorrow. I have linear Hall sensors and instrumentation opamps in the goodie box, no prob. I can TIG a shielded box together for it since I can still TIG. Fitch is loaning me his scope meter (battery powered, digital, with memory) for logging data while I weld mask-down. That'll arrive tomorrow by UPS blue label. I can piss and moan with sleeves rolled up.
I'm learning that part of the problem here is an attitude problem, and I don't mean mine. I either need to get the electrofizz doc's attitude shifted or find a different one pronto.
I'd forgotten that one of my gentleman shooting buds used to work at Guidant, now Boston Scientific. Sent him an email last night. He shook his old-colleague bush a bit and lordy did the fruit fall! One particularly encouraging note was from a Senior Engineering Fellow who happened to be skiing in Taos but answered other Senior Engineering Fellow's call anyway. For those unfamiliar with engineering orgs or academia, few engineers attain the status/rank/title of Fellow. It's a bit like General in the military, except that I think most Fellows are paid better than Generals.
His first comment was particularly encouraging:
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1) Don't worry about this affecting your hobby lifestyle. There are
many things that can be done to limit the risk of unintended shocks.
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wrote:

Wow! I'm savin' that. Thanks, RoyJ!
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