Failure to recognise when an aerosol isn't a droplet 26

[LittleInch]

FacEngrPE dropped this in an obscure post and it reads very well.

Basically the whole epidemiological world though various dieses and viruses were spread by "droplets" which landed on surfaces and then infected people or were sneezed at you.

And a lot of times they are probably right.

But there was a magic 5 micron cut off between droplets and aerosols. Why? Read on

https://www.wired.com/story/the-tee...t-helped-covid-kill/?utm_source=pocket-newtab

So is this a disaster - Well you tell me.
But it goes to show that just because a lot of people write something, it doesn't mean that they originally got the wrong end of the stick and then the error repeats itself until it becomes fact.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Denial]

Or a new planet.

 

[Fischstabchen]

I wonder what an actual epidemiologist would say reading through this thread. I suspect he or she would be impressed that someone was interested in the technical aspects of transmission and equally disheartened that no one even bothered to read their papers.

 

[TugboatEng]

Well, it seems like the epidemiologist wouldn't want anybody reading this paper as it was quite critical of them.

Also, they don't seem to think the public can handle the truth.

“The reason we’re promoting ventilation is that this virus can be airborne,” Van Kerkhove says. But because that term has a specific meaning in the medical community, she admits to avoiding it—and emphasizing instead the types of settings that pose the biggest risks."

 

[LionelHutz]

I have never doubted that you're trying to be serious.

I'm curious, did you see the deleted post?

 

[Alistair_Heaton]

Tug I suspect that their reasons for ventilation are different to ours which is to promote evaporation and the "bio load" falling out off the air in a short time period/distance.

///humour on.

I have dropped plenty of farts which had quite a lot of mass but pretty much zero volume ;-)

/// humour off.

 

[TugboatEng]

We used to have a captain nicknamed "whiskey shits". He is no longer an employee.

 

[Alistair_Heaton]

They actually put a bit of thought into the design for us for our wheel house.

There is an air wall up the middle of the pedestal which they have air blowing through perforations in the panels, from the avionics cooling. Then a negative pressure zone down by our feet.

Its main plus point for me is you don't have to endure stinky fish Friday crew meals. I was spoiled as a child coming from Aberdeen and only ever eating fish the same day as it was landed. The frozen reheated tray meals all smell rotten to me. Thankfully my colleagues see them as a huge treat and there is no problem swapping them for their chicken Caesar salad.

 

[moon161]

Oh geez, I just realize why my good friend, the call center manager has been so extra uptight for the past year and a half. I think he isolated from his girlfriend and his kid for quite some time. I remember almost 20 years ago he was so excited when I got my call times under control probably so he wouldn't have to fire me.

Me I've been 'yeah, I'd rather work from home but there's about a thousand square feet per person in the office and my commute time is half what it used to be'

 

[RedSnake]

I'm curious, did you see the deleted post?

I am not sure if you mean Post deleted or Post edited by him or posts Reported.
But in all three cases the answer is, no I have not.
I might have read something that was Reported and then removed, but in that case, it is not something that has stuck in my mind.

I do not think that his choice of words or his rhetoric is okay sometimes, but on the other hand, I do not think that yours always is either.
And it is because in Sweden it is not an acceptable social norm when discussing or addressing things.
But this is an international site, so after a while here I came to the conclusion that it seemed to be acceptable with this tone and way of expressing oneself at times.
And it's seemed as nobody was particular bothered with it and mostly no one pointed it out when it happened.
So I came to the conclusion that I should just ignore it.
As long as it was not directed at me.

For me, language use has nothing to do with how serious you are about something.
Would almost like to turn it around and say, that it's hard to get so upset and annoyed about something you are not serious about.
Maybe that is a bit to much female logic. ;-)

Best Regards Anna

PS. I have had three mayor conflicts going on in the real world this last two weeks apart from my septic tank problem, so my conflict and kerfuffle account is more then filled up, right now I just want to have some carefree time, and I got my first Pfizer shot today so maybe I need to take it easy.

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[moon161]

1st Pfizer was OK for me, a little sore at injection site, whole body was a little strange for a couple days.

2nd Pfizer, 2 or 3 days of pain, like the flu, without fever and extra secretions/excretions.

In both cases, my wife's reactions were similar but more severe.

 

[Alistair_Heaton]

i had just put down 3500 m2 of newly seeded grass, including shifting the rocks and raking the ground

I got contacted 3 days after my pfizer first jab because I was a bit a a nightmare for them because I didn't catch it when everyone else in the house did.

All I could say was my whole body hurt when I walked in the door and three days later its still hurting but think that's more to do with the garden than the jab.

Have the second one next week.

 

[RedSnake]

My mother have had both shots, she still lives.
Good indication. ;-)
Third day after the first shot, she "complained" that here arm an shoulder aced really bad, before that everything was a piece of cake.
I sade what did you expect.

For Yuguo Li, whose work had so inspired Marr, these moves have given him a sliver of hope. “Tragedy always teaches us something,” he says. The lesson he thinks people are finally starting to learn is that airborne transmission is both more complicated and less scary than once believed. SARS-CoV-2, like many respiratory diseases, is airborne, but not wildly so. It isn’t like measles, which is so contagious it infects 90 percent of susceptible people exposed to someone with the virus. And the evidence hasn’t shown that the coronavirus often infects people over long distances. Or in well-ventilated spaces. The virus spreads most effectively in the immediate vicinity of a contagious person, which is to say that most of the time it looks an awful lot like a textbook droplet-based pathogen.

I have been trying to find some statistics to compare to a similar country, since we in Sweden have just had the keep distance, wash your hands and stay at home rule almost the hole time not as strict as other countries.
I know from reports made during the pandemic that almost all outbreaks have come from people in close gatherings like elderly homes, churches , moskés , chorus singing, vacation maintenance work (LKAB), buildings sites, (North Volt Skellefteå) people coming from around all Europe they got infected at work close quarters and then toke it home and it spread around the community.
The only ones infected with something that might be aerosols is health care workers in intensive care units with respirators.

Best Regards A


“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[LionelHutz]

I might have read something that was Reported and then removed, but in that case, it is not something that has stuck in my mind.

If you saw it, I'm highly doubtful you would have forgotten reading it. It was a rather ignorant admittance of knowing that V/A isn't a constant which makes that whole new apology ring very hollow and meaningless.

What's rather pathetic is that his last post is mostly nothing more than a carefully written rant directed at me about posting that V=m, which I actually never wrote.

 

[RedSnake]

Now you are making a assumption Lionel.
The reason I would not remember something like that, is that I haven't been following this thread that close from the beginning because I could not read the article.
From the little bit I could read and from what LittleInch hade written, I could not understand what this volym, mass, area, constant had to do with it.
And with all the bickering back and forth and with my own problems to deal with, I didn't have neither the energi or the time to analys all of these post and put them into my memory bank.
After I hade the read the article I didn't think that what was written before was that "important".

In the end it's seams to me as the difference is that you chose not to believe in his apology and I do.
He has never been anything then polite to me personally or f-you me as you put it, so I have no personal reason not to believe him.

I have never been afraid to admit when I have been wrong, and I expect to be equally respected for that as for beaning a good engineer.
But I can't expect that if I don't extend it to others too.

Nobody is perfect or infallible, we are humans, not machines, I hope.....

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[LionelHutz]

You either saw it and read it, or you didn't. If you didn't see it or read it, then you can't be a very good judge of the apology.

The expletive wasn't directed at me. It was more or less directed at everyone who had stated it wasn't a constant written in such a way that it strongly appeared he knew it wasn't long before writing it.

As I posted, it's hard to judge the apology unless you judge it with that post.

 

[TugboatEng]

We should consult a paint booth engineer on this. They're experts on aerosol spread.

 

[FacEngrPE]

Tugboat's comment about paint booths reminded me of

https://portal.acgih.org/s/store#/store/browse/detail/a154W00000BOavHQAT[/URL]]Industrial Ventilation: A Manual of Recommended Practice for Design

, This has been my go to reference anytime i needed to know how to control dusts and vapors for an industrial process.

The [link

https://www.acgih.org/

]American Conference of Government and Industrial Hygienists[/link ] are experts in paint booths and all sorts of industrial exposure engineering controls. Here is a link to an older version

https://archive.org/details/gov.law.acgih.manual.1998/mode/2up.

They have now published some COVID-19 Resources which are very to the point.

 

[RedSnake]

You are right Lionel I am not a good judge on that.
But it does not matter, because I never based my opinion on that to begin with.
I do not use that type of thought process, when I decide if I believe someone is serious in a apology or not or in other non technical issues.
A belief or an opinion, can be based purely on a feeling or a hunch it does not need to be based on fact or truth.
I do not see it as a technical issue that’s needs analyzing with a right or wrong answer.
If I had, it would have been a fact and not a belief or an opinion.

I feel, we might not come to any consensus in this, so maybe it’s best just to agree on disagreeing if that’s okay with you?

No hard feelings Anna

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

 

[LionelHutz]

Yes, it's a belief or feeling, but you can't say it's never based on your mind considering any related facts involved. I didn't point it out before, but he posted a "volume is PROPORTONAL to diameter" stinker that stronger appeared to be yet more trolling since he did it right after his previous one had run its course. I'm actually curious if everyone else missed it, or just didn't care anymore? That is yet another reason I didn't buy the fake apology - he made a point of even saying he screws up his constants and proportions seemingly trying to point back to it.

 

[IRstuff]

Yup, trying to move on; some people just can't be changed.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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