I see that Dr Rohn has thrown down the gauntlet.
Last year our faithful lab microwave (food use only, no nasty chemicals please) died, and Kate and myself were despatched to K-Mart to buy a new one. I carried it back across Victoria Park (they only employ me for my muscles) and as a reward I was allowed to take apart the old one (I have simple tastes).
Why, you might ask yourself, is taking apart a microwave considered a reward?
Because, gentle reader, the synchrotron magnetron contains these:
— two toroidal, and obscenely strong, magnets. In figure 1 (above) you will notice that the upper magnet is levitating above the lower. You can use the 15 ml Falcon as a scale guide to estimate how far apart they are.
So this was fun, and provided hours minutes of amusement for various people in the lab. Then I realized that I could save us nearly twelve hundred Australian dollars (which are like US dollars but with a sillier accent).
One of the other postdocs had just planned on using Dynabeads for some some experiments, and was positively giddy with joy when I suggested that she save the lab nearly twelve hundred Australian dollars (which are like US dollars but with a sillier accent) and use my Levitron™ to separate the beads. After all, a magnet is just a magnet, yes?
So with judicious use of Blu-tac we are able to fit about eight tubes on one magnet:
This ticks all the boxes. It’s not just innovative: it’s cheap, reduces toxic waste, recycles microwaves and cures cancer in laboratory rats. I should paint them green and sell them for nearly twelve hundred Australian dollars (which are like US dollars but with a sillier accent).
It’s beautiful, Richard. I have tears in my eyes, truly I do.
And good to see that the use of Blu-Tac spans national lab boundaries.
Richard – that is brilliant. I feel there should be an equivalent of the IgNobels for the kind of ingenuity displayed here and in Jenny’s posts. The ScrapNobels perhaps.
All we need is an institution imaginative enough to run and fund them. (Looks meaningfully at all the Nature employees who frequent these places. Failing that, has anyone insider contacts at the RI? Or maybe Bostick, alleged makers of Blu-tack (spelled with a K at the end on my packet).)
which are like US dollars but with a sillier accent – At risk of facing the wrath of Jenny, who I’ve never heard speak and I suspect has a charming accent, I think you could find parts of the US where this statement is contradicted.
Richard, I gasp in awe at your
pecsingenuity, Sir.hmmm. Thin ice, Brian.
Or as we say in Ohio, ‘thin ice’.
Brian :I challenge you to find a sillier accent than the Australian one — anywhere.
(and if you haven’t heard Jenny talk you can – she was on the Grauniard podcast back in March, I think.)
Henry: what time do you finish work?
The aforementioned Nature employees are but editors, somewhere near the bottom of the corporate food chain — well, in any event, not allowed near any dollars (Australian or otherwise), pounds, pence, euros or other. Very wise, I suspect.
Richard: Inspector Clouseau? John Cleese?
Henry: what time do you finish work?
Depends who’s asking, ducky.
Maxine – you really should come and visit some day.
Just curious. Did you measure the payload lifting capacity of your levitational device?
No, Raf, although before I write it up for Nature Methods I probably should.
When you do, please note that Nature Methods requires that loading is expressed as guinea-pigs per square inch.
Eh, Henry – perhaps you could freeze-dry say three of yours (for replicates) and fedex them to me stat? Guinea pigs are classed as noxious pests in this weird country and very difficult to obtain otherwise.
I will of course acknowledge you appropriately.
Some time ago (I stopped reading a while ago) there was a long thread running on the BBC website magazine pages regarding units of measurement…. often large volumes of liquid are refered to in terms of how many olympic swimming pools they’d fill, weights in terms of elephants, length in terms of double-decker buses. Anyway, this obviously got rather wacky and good fun with new suggestions and tangential oddities flying around.
So, electrictromagnetic field measurements are now to be known by their new SI unit: guinea-pigs per square inch. Whatever next?
electrictromagnetic huh? Wow! A new SI unit and a new force of nature.
I am on a ROLL people!!
Ian, you should take a look at this site.
Eh, Henry – perhaps you could freeze-dry say three of yours (for replicates) and fedex them to me stat? Guinea pigs are classed as noxious pests in this weird country and very difficult to obtain otherwise.
Dang it, my freeze-drying equipment is on the blink.
In any case my guinea pigs are not for use as scientific … er … guinea pigs. I guess that you could find GPEs (Guinea-Pig Equivalents) from Australia’s native
undergraduatesfauna. Very small wombats?@Richard – Your experimental set-up looks very similar to somethin in my kids toy cupboard.
Mine are better.
Are you SERIOUS that magnets in premanufactured holders cost that much in your adopted country? My jaw hit the floor.
Your ingenuity is that much more appreciated.
Meanwhile, might I humbly suggest that you arrange your test tubes around the side of the magnet? When your magnetic beads are drawn up against the side in a thin brown line, it makes life much easier when you’re decanting supernatant. You just go hit the bottom with the pipette tip and no worries about nudging the sludge aside.
Alright, I’m going to have to drag out my get-up for making electrolytically sharpened tungsten scalpels for microsurgery. But it’ll have to wait until early July when I’m back in the right lab. Of course, this principle was already used by Hubel, D.H., Science, 125, 549, but although I’m not the one who came up with this, I got to reuse a converter from an old dissecting microscope that dated back from before the war, I think, and salvaged at least the converter when I moved to a new place and the old one finally closed. Lots of cool stuff hanging around old labs.
I see that Dr Rohn has thrown down the gauntlet.
Shame on her for discarding it. Glad to see you picked it up for reuse…
I am glad that they work for you, and that they are all very nice, but what is important in magnetic separation is the product of magnetic field and magnetic field gradient.
Those look to be ferrite magnets which have a maximum field of a few tenths T. The field gradient in the open field configuration you have scales as the dimensions of the open space. Using pole pieces of iron, you can get the field at the surface of the iron up to the saturation of iron, about 2 T.
A source of magnets with much superior magnetic properties are defunct hard drives. Those typically use rare earth magnets, (typically Nd2Fe14B) which has about an order of magnitude better properties than ferrites. They also often use Fe-Co alloys as pole pieces which have a saturation magnetization of about 2.4 T.
I think you could easily get 100 times higher separation forces by using magnets from a hard drive instead of from your microwave.
David. Nice.
But… in English that translates to?
Well, I understood it. To me the final sentence was clear enough: Task that potrte of keeping the strong forces easy with the 100mal to
start off, being used magnets of a hard program of reading in the place of its microwave.
What’s to translate?
As an engineer I am familiar with many English units, BTUs, feet, inches, pounds and use them all the time. Magnetic field doesn’t come in English units, or rather the English unit is the same that everyone else uses, either the Tesla (T) in SI, or the Gauss, in cgs units. It is sometimes called electromagnetic units, but I find them hard to keep track of so I always use SI.
But the microwave was there, the hard drive wasn’t.
So should we all be pulling our microwaves apart then?
Are you SERIOUS that magnets in premanufactured holders cost that much in your adopted country? My jaw hit the floor.
In the UK, the product linked to is £450. Which is 940 Aussie dollars.
Hah, Scott, you’ve given me a great idea.
We’ll test David’s contention by putting some microwave magnets on a hard drive, and some hard drive magnets on a (different) microwave, and see which continues to operate effectively.
so not only are they hellishly expensive, we also get screwed by the “It’s such a loooooooooooooooooong way to Australia” markup on all imports.
@David: Is it the same kind of magnet no matter what the memory capacity? That is, can I pull apart the hard drive from an ancient laptop, or tower, with something like 8 Mb, and get the same bang for my buck? I’m willing to give it a shot if so. (I presume it is yes, and am itching to get out the screwdrivers and mallet as soon as I get home.)
Heather, if you do, take apart the drive itself, and use teh individual disks as coasters. You’re probably best using some sort of lacquer on them though. And maybe a cork underside. They sure are shiny and pretty though!
Heather, pretty much. They are part of the drive mechanism that moves the arm that holds the heads. The older drives are probably better because they had to be bigger, so to get decent performance they needed bigger and stronger magnets. I haven’t taken apart any recently, it has been at least 10 years.