# Anyone have any random nerdy facts?

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And I'd have expected MIL spec temperature range and part screening. What I'm wondering is if the article just left those bits out; I skimmed it and didn't see a definitive statement that it's really a stock, off the shelf item, exactly the same as you or I could buy. We can buy an item with the same functions and interfaces (electrical, logical, and physical).

Indeed, which is why I'm only talking about parts upgrades, not design changes. Back in my satellite days, we used MIL-STD-1750 based onboard computers long after they were obsolete. We only switched to something newer when we had a specific onboard function that needed it, and the 1750 chips were damn near impossible to find.
Thanks for confirming my thoughts.

So, you ignore the units. Just 84-x, not "84 rocket motors minus your age". And "later in the year" covers about 63% of the year (as of today). I'm not impressed.
ok... a simple math fact that always works. Every odd number has the letter e in it, at least in English.

E is the most common letter, and why in morse code is it simply a dot .

to know what wrench you need for a particular hex head bolt or nut:

double the diameter, and minus a 1/16"

ie: a 1/4" bolt requires a 7/16" wrench.. (1/4 * 2 = 1/2, 1/2-1/16 = 7/16")

works up to 3/4" if I recall
I worked in a garage for awhile- off the top of my head...
5/16" bolt uses 1/2" wrench
3/8" bolt uses 9/16" wrench
7/16" bolt uses 5/8" or 11/16" wrench (the nuts are usually 11/16", bolt heads can be 5/8" or 11/16")
1/2" bolt uses 3/4" wrench
A more general rule is the wrench size is about 1.5 times the bolt diameter.

In larger sizes hex nuts come as "hex nuts" or "heavy hex nuts" so there are 2 different sizes.

Alphabet in order of most common to least common:
ETAONRISHDLFCMUGY...
I don't remember anything past Y.

I remember that from probably around 50 years ago. I wonder if the probabilities have changed over the years?

I long for reasons to say deuterium.
I answered "what is deuterium" to a Jeopardy clue yesterday. The correct response was "what is tritium." Missed it by that much ....

to know what wrench you need for a particular hex head bolt or nut:

double the diameter, and minus a 1/16"

ie: a 1/4" bolt requires a 7/16" wrench.. (1/4 * 2 = 1/2, 1/2-1/16 = 7/16")

works up to 3/4" if I recall

I worked in a garage for awhile- off the top of my head...
5/16" bolt uses 1/2" wrench
3/8" bolt uses 9/16" wrench
7/16" bolt uses 5/8" or 11/16" wrench (the nuts are usually 11/16", bolt heads can be 5/8" or 11/16")
1/2" bolt uses 3/4" wrench
A more general rule is the wrench size is about 1.5 times the bolt diameter.

In larger sizes hex nuts come as "hex nuts" or "heavy hex nuts" so there are 2 different sizes.
It's not that simple. Looks like the exact size is rounded to a given size. I get 1.5xbolt size + either 0, 1/32, or 1/16 depending on size for standard bolts.
Here's a chart for bolts up to 4" https://pacificcoastbolt.com/wp-content/uploads/2020/07/wrench-charts.pdf
I repaired die casting machines and 3/4" and 1" bolts were common. Larger ones were almost always socket head cap screws. A 1-1/4" screw used a 1" Allen wrench (the largest I kept in my tool box). Larger ones we went to Maintenance and borrowed one (along with the 3/4" drive impact wrench).

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Recently I had to buy some metric set screws. They have inch fraction hex (Allen) sockets!! But metric threads on the outside. Ok, whatever, man.

It's not that simple. Looks like the exact size is rounded to a given size. I get 1.5xbolt size + either 0, 1/32, or 1/16 depending on size for standard bolts.
Here's a chart for bolts up to 4" https://pacificcoastbolt.com/wp-content/uploads/2020/07/wrench-charts.pdf
That has both hex and heavy hex nuts in it. I thought I spotted a mistake but it's just a glitch in formatting- heavy hex nuts for 5/8" diameter bolts require 1 1/16" wrench, in the chart it looks like 11/16". If you need accurate dimensions for nuts look up ASTM A563 or ASME B11 or B18.

I designed a circuit for driving deuterium lamps. They produce a nice peak at 656nm which is used for calibrating monochromater optics.

Cool. How much different is that from a protium lamp?

I designed a circuit for driving deuterium lamps. They produce a nice peak at 656nm which is used for calibrating monochromater optics.
What is a deuterium lamp? It seems like they glow in a specific frequency? Why would you want deuterium?

Cool. How much different is that from a protium lamp?
How much different is that from a lava lamp?

What is a deuterium lamp? It seems like they glow in a specific frequency? Why would you want deuterium?
Deuterium lamps: UV spectroscopy is one major use. Some have filters to narrow the UV range. It can test a material for it's absorption, reflection, or iridescence to special UV bands. I've designed high-speed sorting machines that use this to detect insects and holes in agricultural products. There's also information is infrared for organic products. Lasers are very narrow band not as useful because is doesn't illuminate a large area all at one time.
(Here's one of the machines I designed: )

Useless nerdy fact of the day.

All the world’s bacteria stacked on top of each other would stretch for 10 billion light-years. Together, Earth's 0.001mm-long microbes could wrap around the Milky Way over 20,000 times.

What is a deuterium lamp? It seems like they glow in a specific frequency? Why would you want deuterium?
Deturoum also has an emission line that is absorbed by water on the air. A way to measure humidity

Deuterium lamps: UV spectroscopy is one major use. Some have filters to narrow the UV range. It can test a material for it's absorption, reflection, or iridescence to special UV bands. I've designed high-speed sorting machines that use this to detect insects and holes in agricultural products. There's also information is infrared for organic products. Lasers are very narrow band not as useful because is doesn't illuminate a large area all at one time.
(Here's one of the machines I designed: )

I have always wondered why all those sorts of videos use the same song?
Also what was up with the blue light, UV isn’t visible?

I have always wondered why all those sorts of videos use the same song?
Also what was up with the blue light, UV isn’t visible?
Lame soundtracks are available with no royalties!

Multi-spectral imaging. Visible light has a majority of the information for the husk-processing walnut-sorter application.

Lame soundtracks are available with no royalties!

Multi-spectral imaging. Visible light has a majority of the information for the husk-processing walnut-sorter application.
1 I get that but it always seems to be the same song, I guess I’m just going crazy…

2 ok I was wondering if it was similar to the time that a guy I knew who was doing MRI research had a film crew add a bunch of cool tech lights to his MRI so it looked like something was happening.

It seems weird that deuterium and protium should have spectra big enough to matter, but you can't argue with facts.

It seems weird that deuterium and protium should have spectra big enough to matter, but you can't argue with facts.
It's molecular emission from D2 or H2; mostly wide bands of UV. D2 provides stronger emission in the deep UV than does H2. One of the guys in our research group at UGA used a D2 arc lamp for his work. Mine involved a xenon arc lamp for an instrument that ended up as a totally useless dead end. New knowledge, though, so it got me the M.S. degree.

Oh, I understand what the difference is. It still seems weird that increasing, even to the point of doubling the mass of the nucleus would change the behavior of the electrons to anything more than a very VERY tiny degree, i.e. a degree that matters. Weird or not, it obviously does.

Mine involved a xenon arc lamp for an instrument that ended up as a totally useless dead end. New knowledge, though, so it got me the M.S. degree.
One of our products uses a xenon flashlamp for UV/Vis/NIR work. Up to 500Hz flash rate, I think with results out to about 6abs of range.

There was quite a bit of work needed to get the results that good. It also has a diffraction grating on a BLDC motor for wavelength selection. That has a shaft encoder with up to 14 million positions for one revolution. Tricky control loops, but nifty tech .

How NOT to make a sugar rocket..... Should be getting a Darwin award shortly. It's only a matter of time....

How NOT to make a sugar rocket..... Should be getting a Darwin award shortly. It's only a matter of time....

How did that end hold pressure? Also no nozzle.

How did that end hold pressure? Also no nozzle.
Nozzle-less motors are practical for mixtures that don't chuff easily and have a fairly high burn rate. A longer core is needed for such motors.

The coring rod should leave around one diameter of un-cored propellant at the forward end to hold pressure. I didn't watch the whole video to see whether that was done.

The sad thing isn't that this guy may win a Darwin. It's that impressionable youngsters will look at that and think "Hey, it looks easy, let's try it!" If they're lucky they'll merely have to explain the huge cloud of smoke throughout the house, and the burn marks on the kitchen ceiling. **IF** they're lucky...otherwise