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No, good thermal management with a chiller, active thermal compensation, and glass scales make um precision on that scale reasonable. 10-100x better? Sure, you’re getting into machines where the room to keep them happy is significantly more expensive that the machine…

Let Kids Be Loud 1 year ago

Ok but my neighborhood children have started using electric leaf blowers as jet propulsion on skateboards. I have insisted they use hearing protection, but the rest of us are shit out of luck…

It’s fun seeing an uptick of rhino/grasshopper content here lately - two articles in a week?! The McNeel extended universe is a fun place to play around in, and I’ve met lots of great people since I started working on Rhino.

It doesn't really detect stringing together latinate nonsense, so all of my coinages got perfectly coherent definitions. On the flip side, I guess if you're erudite and willing to butcher other languages for sport, nothing has ever stopped you from making up perfectly quasiaryiumaryesque words.

I'm not running the show, but I am working at a place that does this. One time fee for a perpetual license for the current major version, free support, and historically ~6 years of updates per version.

Users tend to be quite happy about it, and we're profitable enough to pay comfortable salaries and have...a lot...of runway.

Of course, this model is possible because there was never any outside investment.

If we're "unbundling"/giving into "free market" nonsense in a highly regulated area, I just want to be able to pay reasonably proportional fee for musical instruments and get a guarantee that they'll be carry-ons, and not destroyed in the cargo hold. My only other alternatives are buying first class tickets or flirting with the gate agent (...works remarkably well...).

I was using it to build a dilatometer - an instrument for measuring thermal expansion curves of materials. Theoretically simple, in that you take a sample of something and measure how long it is while sweeping the temperature around. In practice, you need very stable ~um measurements and lots of care to make sure all other length changes around the sample cancel.

In the real-world, they're often used for precision gauging for in-process metrology.

LVDTs are fun! I bought one for a project a few years ago (since abandoned), and have been slowly designing my own readout electronics for them. Three revisions later, and the performance is very good - to the point that I've bought more increasingly precise measurement gear to benchmark how it's performing. Currently, I'm testing it against some good glass scale linear encoders, and a capacitive gauge with a single-digit nm noise floor.

So many don't buy an LVDT, I guess.

As a consequence of the aging members, a lot of churches (particularly the less virulent mainstream protestant flavor) around here are merging congregations and getting demolished, to be replaced with more apartment buildings. Sometimes the parishioners will fight the good fight and get concessions made for affordable housing or other social goods.

I second this; this is super bad advice. CO2 systems are comparatively safe from an eye damage perspective - unless you take a direct hit, (...don't, seriously, that's what interlocks are for...), 10.6um is strongly absorbed by your eye and you'll get superficial thermal damage, maybe cataracts or a corneal burn, but it won't get focused on to your retina so serious vision loss is unlikely. Polycarbonate safety glasses have a crazy high optical density at 10.6 and are suitable protective eyewear.

The situation for visible diode lasers is much worse. Sure, the power tends to be lower, but they're still powerful enough that looking at a diffuse reflection will result in dangerous power densities on your retina. Unfortunately, the brain is really good at hiding this sort of damage, so it's possible to not notice until it's too late.

1.064um fiber lasers are the worst of both worlds. Very high powers, invisible so you have no idea how much stray light is getting out or if you're staring at a reflection, and expensive + hard to verify safety glasses.

I like doing things with high power lasers (next up for the collection is probably a 355nm ns system?), but am glad that I had to take a lot of laser safety training before I bough my first big laser source.

Yeah, but that lineage of banjos became 17-fret tenor banjos in the teens, which are still really nice instruments if you play Irish trad tenor and don't need the volume of a 23-fret. So, not all a bad thing.

Well, there isn't a meaningful inner product, so how can you speak of parallelograms? The geometries are definitely weird! Once you leave p=2 and break the rotational symmetry around the origin, the only isometries in your geometry are signed permutation matrices - so geometry "over here" looks different from "over there". Angles aren't really meaningful, I guess.

The other interesting thing is that duality kicks in (or maybe becomes non-trivial, since it's always there) and derivatives naturally start to live in a different space. If you take the particularly natural definitions of general cos_p and sin_p I alluded to, you get a nice parameterization of the unit p-circle as (cos_p(t), sin_p(t)) - but if you differentiate this wrt t, the resulting tangent vectors don't lie on the p-circle. Instead, they form a parameterization for the q-circle!

One thing this doesn't touch on is that there are multiple meaningful definitions of pi-like constants for the p-norm unit circle that don't necessarily agree with each other in p != 2. Defining pi as the area of the unit circle gives an entirely different set of values that satisfying some wonderful properties - in particular, that definition of pi turns out to be the periodicity constant for a (arguably) natural set of trigonometric functions for the p-circle. Furthermore, pi(p) = 2 Beta(1/p,1/p)/p...

However, this (circumference/arc-length based) definition of pi does have a fascinating property for conjugate p,q: pi(p) = pi(q)

"Squigonometry: The Study of Imperfect Circles" is a very fun reference for this sort of stuff.

This is definitely a big thing! Having a group of musical friends to play with is a lot of fun, really helps keep them interested, and is the only way to learn how to play music with people. I wish I/my parents put a little more effort into that, because there's a lot of musical "soft skills" that I'd like to be better at. For better or worse, the Irish Trad scene (outside of Ireland at least) is quite focused on drinking beer and playing tunes in pubs late into the night; so that was off limits to me at the time...

Can confirm, went to a school like that but without a namesake building. They can either always admit someone else, or more often, just not bother because educating kids is an expensive loss leader for the endowment even with full tuition. It definitely seemed like there needed to have already been a family building or two before you got to campus if you expected much immunity because of that...