That study is interesting because they used SEM to image the plastic afterward, and you can see how the plastic surface has literally been torn up on a microscopic level simply by touching hot water.

Plastic has a low-energy surface, which means it doesn't take much energy to tear it apart. Even Brownian motion is enough, which is pretty wild.

If you need to filter "one and done" (like pumping air into a hospital operating room), that's where you need HEPA. Most home air purifiers mix the clean air back into the same room, so MERV is closer to the ideal sweet spot.

It's also important to buy reputable brands of MERV filter, ideally ones which have a large number of folds (surface area) like the 3M 1900 MPR. In recent testing about half of filter brands scored well below their claimed MERV rating:

https://www.youtube.com/watch?v=FKAVek1YaSQ

Positive pressure systems are great, love 'em, but there's a quantitative mismatch in this case. Above ~1 ACH your HVAC costs will go through the roof (even with heat/humidity recovery), but for effective filtration you need 6-8 ACH to catch the larger dust before your lungs do.

I too would like such a "shy" air purifier, but manufacturers always seem to go the other way: when occupancy is detected they increase the fan speed.

Best option IMO is just to get an air purifier with a good CADR-to-decibel ratio and then (again) size it correctly. A surprisingly good option is something called the Airfanta 3 Pro, which is basically like those wildfire filter boxes except it uses PC fans.

  >microwaving in plastic bowls

For instance the same thing happens with plastic tea bags in hot water: https://www.sciencedirect.com/science/article/pii/S004565352...

Saying HEPA filters remove "99%" of microplastic is pretty misleading.

Most of the mass in airborne particles is in the larger sizes of visible dust. However these particles will "fall out" before they reach the air purifier.

The best advice isn't "use only HEPA" or (an odd one, from this article) "use filters with multiple stages," it's to have an air purifier where the Clean Air Delivery Rate (CADR) is matched to room size. For filtering large dust you need a lot of air flow, aim for 6-8 Air Changes per Hour (ACH).

Also the CADR on the box is always on the highest fan speed, which is always way too loud for constant use in an occupied room. So ideally you want to size the air purifiers assuming a fan speed generating 45 decibels or less. HouseFresh is an excellent review site that publishes these numbers.

Most people dramatically undersize their air purifiers, or run them on a very low fan setting, and then they throw up their hands and say that air purifiers don't work.

Thanks, I really needed this post. I'm saving this for when people inevitably try to re-write history by saying "we didn't need Elon, because did anyone really doubted space-based AI would be the winner?? It was obvious all along because blah blah... "

  >Here's an AI-generated fake video of large transformer manufacturing. It's about half wrong.[2] But right enough to be worth watching.

You probably got a lot from this video, because you know which half is wrong. I'd probably get negative knowledge from this video, because I don't.

This may be a new incarnation of the "curse of knowledge," where one over-estimates the value of AI slop if they already know the subject...

  >that’s not good enough for real world manufacturing and simulation

In theory pi has infinite places, sure . In real-world practice (vs math-lympics) you never need more than 100 digits, and indeed you rarely ever actually need more than 5.

Why doesn't it work to "just" throw more bit-width and more polygons at it? Who out there actually needs more than that (vs who just thinks they do)?

With very low orbital launch costs, it's trivially true that space would become cheaper. Solar panels have no atmosphere/night/seasons and are always pointed at the Sun, no cover glass for hail, no 24h battery either. Radiators are 1/10th the area of PV which is very doable.

The question is, where exactly is the tipping point between those two extremes, and will Starship reach that? Opinions on this naturally bifurcate depending on one's feelings about Elon Musk.

I wouldn't be too worried because SpaceX engineers put a great deal of effort into reflection mitigation, including developing a space-rated mirror able to have an RF signal fire transparently through it.[1] The strategy is to bounce all the sunlight away from Earth, which makes satellites darker than even (hypothetically) covering a satellite in Vantablack.

[1] https://youtu.be/MNc5yCYth5E?t=1717

  >corners where 3 fillets meet

* Intersection. Conceptually the simplest, the chamfers would just be joined by the solid addition of all three fillet surfaces, creating three new sharp corner edges that meet at a single vertex.

* Rolling sphere. Imagine an idealized spherical "thumb" smoothing out caulk. The middle would be joined by a new spherical concave surface, tangent to all three fillets. Also generalizable to convex fillet intersections, smoothing out sharp corners.

* NURBS, with adjustable parameters or even control points, eg when you want a little more "meat" in a corners for strength of a part.

* Flat corners, for chamfers (what do do when N>3 corners meet?)

* What else?

Ideally you might be able set the corner type separately for inside vs outside corners, or on a per-vertex or (in the most granular case) per-incoming-edge basis? Is that crazy?

How do saddle corners[0] behave? Does it just "work out" and (by some miracle) uniquely resolve for all permutations and corner types?

It certainly gets complex quickly!

[0] center, where the cubes all intersect https://entitleblogdotorg3.files.wordpress.com/2015/02/esche...

I'm equally not "surprised" by their bad behavior, but that shouldn't stop us from condemning Google for unethically misleading people and engaging in browser monopoly abuse.

---

EDIT: holding up (hilariously) RIAA lawyers as ethical role models only proves my point, thanks.

The two scenarios are pretty easy to distinguish. If the explosion occurred near the poles (above 75° latitude), it's most likely a random debris strike.

Sure enough, despite the fact that only 2.1% of Starlink satellites[0] are in orbits that go above 75° N/S, Starlink-34343 was one of those satellites.[1]

[0] https://planet4589.org/space/con/star/stats.html

[1] https://www.amsat-uk.n2yo.net/satellite/?s=64157

Synthetic textiles (clothes, upholstery, carpet, dryer exhaust, washer drainage) are of course the biggest culprits, with most of that trapped indoors with us, or co-located with human activity. If you have a dog that may change the mass fraction, but the MP exposure remains the same (or worse due to additional wear).

Road and tire wear is the other big contributor, again co-localized with population density. That's one of those nuanced cases, because a large fraction of the tire mass is actually natural rubber. The synthetic additives make it categorized as 100% plastic, but this may not accurately reflect reality in terms of the chemistry or hazard-based analysis.

Plastics are chemical "sponges" that will soak up pollutants over time from the environment (brominated fire retardants, bisphenols, PBCs, pesticides, phthalates, heavy metals, etc) and deliver them in a concentrated dose into the body.

https://www.sciencedirect.com/science/article/pii/S030438942...

https://www.researchgate.net/profile/Verla-Wirnkor-2/publica...

It was just an aside anyway. My main point is that MPs are vehicles for toxins, which addresses the original question about how (supposedly inert) microplastics can cause harm.

Thanks again for setting me straight, I must have misremembered.

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