I learned that hazelnuts are cracked by pressurizing air and then quickly releasing the high pressure.I suppose this would kill any microbe and perhaps break up any virus, for sure it would get rid of any pests and their eggs in linnen and clothes. No?
-- pashute, May 29 2022

High Pressure Air Dry Cleaning
[xaviergisz, May 30 2022]

//I suppose this would kill any microbe and perhaps break up any virus, for sure it would get rid of any pests and their eggs [...]//

My instinct is probably not, almost certainly not and maybe/sometimes respectively, for any reasonable pressure swing.

Changing the atmosphere by itself may cause damage or prevent growth in itself of course. But if we're just looking at the pressure drop, I don't think there's much scope to do a bacterium or virus in, because they don't contain pockets of air.
-- Loris, May 29 2022


Using a pressure cooker is a well known method of sterilising glassware. You could probably do use a pressure cooker to sterilise tough clothes.
-- xaviergisz, May 30 2022


How do bacteria do in a vacuum?
-- Voice, May 30 2022


//Using a pressure cooker is a well known method of sterilising glassware.//

Yes. Raising the temperature and pressure does them in. Microbiology labs use autoclaves to do this. This effect is mostly the high temperature (121°C), the pressure (about 1 extra atmosphere) is I think basically incidental. I'm not sure if lab coats are autoclaved or just washed with lots of bleach, but the process isn't particularly gentle on them.

Google gives a link to a page I can't read which says bacteria are killed at a pressure of 60,000 pounds per square inch. But that's pretty high - over 4000 atmospheres. I found a scientific review and eyeballed the free preview - it also says it varies, but includes a graph which shows /Paracoccus denitrificans/ (which is apparently typical for vegative bacteria), which survives perfectly fine up to 300MPa (about 3000 atmospheres) and is basically completely done in by 450MPa (4440 atmospheres).

//How do bacteria do in a vacuum?//

Bacteria vary immensely in their nature, some do much better than others. Long periods in a vacuum will dry most things out... but apparently not /Deinococcus radiodurans/ (I assume as spores).
Brief periods I think many are totally fine with - particularly any which are on the inside of a clump.
-- Loris, May 30 2022


I'm talking about a sudden pressure DROP that should hopefully pop any insect and possibly even affect their eggs, and maybe affect microbes and viruses, although they don't have air pockets. It's worth giving it a try, but after reading studies about pesticides in silos, following your remarks, it most probably won't work.

I must say that the search for insects and air pressure did bring me to quite a few interesting articles about insects, one called "It's Not a Bug, It's a Feature: Functional Materials in Insects", another "Survival Sounds in Insects: Diversity, Function, and Evolution". and then "Why Giant Bugs Once Roamed the Earth", and "Fly Like a Fly" about the air pressure that flies build up with their wings to fly.

The article that seemed most relevant mentions pressure once, off topic: Role of Modified Atmosphere in Pest Control and Mechanism of Its Effect on Insects.

The air-pressure-alone idea by [bungston] from 2004 is very similar, but not completely equivalent. Thanks [xaviergisz] for pointing it out.

Hi [Loris], nice talking to you, for the first time, I think. If you can't read the page Google showed you, how did you get so much info about what it says?
-- pashute, May 30 2022


//use pressure to replace washing//

I will have nightmares about your shower cubicle.
-- pertinax, May 30 2022


//Hi [Loris], nice talking to you, for the first time, I think.//

I boggled at this. We've both been here for 20 years. I've annotated your ideas; you've annotated mine. Have you never responded to one of my comments directly before?

//If you can't read the page Google showed you, how did you get so much info about what it says?//

I could only read the snippet shown on the search page. The page itself said "451 Unavailable For Legal Reasons Sorry, this content is not available in your region."
So I read another page instead. Which did seem consistent with the snippet, however it didn't seem to endorse anything illegal in my region.

I don't know whether a pressure drop would affect insects or their eggs. It seems plausible.
-- Loris, May 30 2022


If you just need a sudden pressure change, maybe a shock wave would suffice (e.g. produced by a small explosive).
-- xaviergisz, May 30 2022



random, halfbakery