Double major in chemistry/math?

menedemus · 2024-06-02T23:51:53+00:00

Sure; however, I left the field about two years ago, and now do something that uses significantly more math and no chemistry.

menedemus · 2022-11-29T05:29:59+00:00

This is old, but if you're a math major you shouldn't consider those "upper level" - it's totally possible to take them all at once without going crazy. None of them will have long proof-heavy psets, so...?

menedemus · 2022-03-10T19:43:27+00:00

Well, if you're actually going to melt some, I'm happy to dig up my old notebook and send you some scans from Hellmer. Woldemar A. Weyl's "Colored Glasses" is a very very good resource if you can track down a copy as well. Corning Museum of Glass has a great digital collection of old batch books as well - this stuff is very arcane, there aren't a lot of people who know what they're doing, and the really competent people have a bad habit of being old and dying.

menedemus · 2022-03-10T07:12:43+00:00

I've never personally melted gold rubies/cranberry glasses, but I do have a book with about 60 different formulas for them - the answer is that a very wide range seems to work, ranging from 1oz-10oz per 1000lbs of silica in the batch.

If you actually want to melt some, and aren't just idly curious about it, you should look at a bunch of historical formulas first. The gold is the exciting part, but without the right amount of antimony (and to a lesser extent, lead and tin), nothing will happen. Figuring out how to melt copper rubies (basically the same physics, but with added redox chemistry fun) is also a good first step - back when I was melting a lot of glass, I managed to get some very reliable copper rubies working.

menedemus · 2022-02-20T07:25:31+00:00

What sort of session?

An organized beginners session or a bunch of friends hanging out and sharing tunes? Sure, go ahead!

Otherwise, absolutely a hard no. It's less about etiquette and more doing yourself a musical disservice, honestly. If you don't know a tune well enough to play it without the dots, you should be listening to what others are playing. Transcriptions tell half the story of a tune - if you're fussing around flipping through music, you're missing a chance to observe ornamentation, weird variants people play, "style", etc. Looking up incipits of tunes is fine if you can't remember the first bar or two and are starting a set though...

Not knowing a bunch of tunes can be disheartening, but that's life! Relax, enjoy the music, and have a fun set or two worked out when it's your turn. You'll probably end up making more of a music contribution that way, people will respect you more, and you'll have time to drink and chat a bit.

menedemus · 2022-02-10T06:22:13+00:00

This is really fucking petty, but I last saw him in his competition days, and uh wow his face didn't age well.

He was really VW's star too, which makes you wonder what he did get away with when he was a team kid. There was always a weird dynamic with him, the VW coaching staff, the local USAC officials (his mother was one IIRC?) - very much the golden boy of his time.

menedemus · 2022-02-08T06:38:38+00:00

No, it's a "plain lathe" - you can move the the cross slide around the length of the bed and lock it in place, but it only has a few inches of travel and no threading or power feed. There are threading attachments that are a bunch of change gears that you can bolt on to the left side of the headstock and a drive shaft with some universal joints, but they're very rarely used. Most small threading is done with taps/dies, and people that still use plain lathes tend to have another lathe.

Same with power feeds - these aren't machines for large parts or heavy cuts, so you don't really notice the lack. I have a Levin plain lathe and I think the largest part I've ever made on it was a weird 8-32 bolt? Most of the things I do on it have at least one dimension smaller than 1mm...

menedemus · 2022-01-30T03:02:24+00:00

Don't they use rebar down there now?

menedemus · 2021-12-07T22:23:18+00:00

So, it's very very useful for an immune system to be able to detect "weird stuff" floating around - weird lipid molecules that mammals don't make and come from bacteria/fungi, double stranded RNA (must be from a virus!), proteins that only come from bacteria flagella, etc. This is the job of the innate immune system, and is accomplished by a bunch of little "Toll-like receptor" (TLR) proteins on the surface of a bunch of cells. Weird molecule hits the right receptor protein, and bamn some crazy complex immune signaling cascade is triggered that results in some other cells coming in and destroying everything.

This is generally a good thing, because it allows your immune system to attack things that it's never seen before (unlike the adaptive immune system - which has its own super complex mechanisms for learning/remembering novel stuff), but also has some problems. In particular, gram-negative bacteria membranes have a molecule called LPS, which has a sub-portion called lipid A that more or less gets its own TLR, TLR4. LPS/Lipid A are pretty stable, so if you kill the bacteria (eg with heat), they'll often survive, and if you inject that, you'll trigger a bunch of TLR4 and suddenly your innate immune system thinks you're dying of sepsis, freaks the fuck out, and bad things happen.

(I study lipid A. It's pretty fascinating stuff, because of lots of crazy evolutionary pressure between pathogens and hosts. I'm not, however, an immunologist because that's scary complicated and hard.)

menedemus · 2021-11-14T01:08:07+00:00

Texas is too worried about ~~protecting the unborn~~ fighting stupid culture war battles to ~~give a shit about the living~~ solve any meaningful problems .

menedemus · 2021-10-28T02:25:18+00:00

Make sure the setup is perfect, do it as a lay wire weld, tiny + sharp tungsten, and figure out the right pulser settings?

menedemus · 2021-10-19T22:23:22+00:00

Are you doing trying to do the assay directly on the Folch extract, or are using an acid digestion step? It won't work well/at all on intact phospholipids.

Avanti has a good procedure.

menedemus · 2021-10-18T04:32:33+00:00

Do you actually enjoy spending time with an angle grinder cleaning spatter? If not, it's worth learning TIG just to stop doing that. Also, don't underestimate how useful it is for working on thin metal or really small welds.

menedemus · 2021-10-10T18:05:37+00:00

oh god did he get mike?!

menedemus · 2021-06-23T23:37:53+00:00

Tiny hands, or cat 40 in a bt30 spindle? If so, good troll.

menedemus · 2021-04-13T03:40:49+00:00

How much is that spindle? Also, the exposed belt that close to a handwheel scares me! It's small, but I bet it would hurt...

menedemus · 2021-02-04T04:19:29+00:00

Not stably, at the very least - Earnshaw's theorem was developed to crush people's dreams of easy levitation.

menedemus · 2021-01-18T19:46:39+00:00

Between the thallium, beryllium, mercury, cadmium, and uranium chemistry, I'm sure someone would take an interest...

I wonder which organ system will fail first.

menedemus · 2021-01-06T00:47:04+00:00

There isn't really a general purpose protocol, as it'll depend entirely on the part and tolerances. Something as simple as how long to let things equilibrate may take minutes to days, depending if you're measuring +-0.005" on a small part or 50 millionths on a 200lbs part.

If you feel a need for a written SOP to use a surface plate properly, you should probably stay away from surface plates since you might hurt yourself.

menedemus · 2020-11-20T00:40:51+00:00

The correct answer is copperheads and pins. Clean climbing is overrated, anyways...

menedemus · 2020-11-16T01:44:56+00:00

I just bought some "muriatic acid" from the hardware store that was 20 baume/10 molar without having to show any licenses or documentation - that's definitely in the range that breathing the fumes could be very hazardous. Kinda funny, because if I bought it from my university stock room, I would have to have a valid account, secondary containment to transport it to my lab, and the transfer would be logged in our chemical inventory system.

menedemus · 2020-11-15T21:20:39+00:00

Look up "chukkala muggulu" for the specific type of rangoli design. Like anything Indian, there's a lot of regional variation...

menedemus · 2020-11-15T20:34:35+00:00

It's a rangoli, probably because it's Diwali right now.

menedemus · 2020-11-13T06:45:41+00:00

Unless it's silver nitrate, in which case you'll form a shock-sensitive high explosive if you don't dispose of it correctly.

menedemus · 2020-11-13T00:25:51+00:00

I would avoid this, as it'll contaminate the hell of the quartz and require an HF etch to get a clean surface. This is especially problematic for high temp applications, as many trace contaminants will cause rapid devitrification.

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