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| Laboratory testing of face masks for the suppression of Covid-19 transmission (Page 2/2) |
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rinselberg
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NOV 21, 12:18 AM
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Let's kick this off (very logically) with the Original Post or "Message #0" as I sometimes like to call it--a "nod" to the forum software's message sequencing number system.
"Low-cost measurement of face mask efficacy for filtering expelled droplets during speech"
Emma P. Fischer et al; Science Advances 02 Sep 2020.
https://advances.sciencemag...ontent/6/36/eabd3083
| quote | | We have demonstrated a simple optical measurement method to evaluate the efficacy of masks to reduce the transmission of respiratory droplets during regular speech. In proof-of-principle studies, we compared a variety of commonly available mask types and observed that some mask types approach the performance of standard surgical masks, while some mask alternatives, such as neck gaiters or bandanas, offer very little protection. |
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That research report has now been summarized in a brief (3+ minutes) video on YouTube. The measuring device involves a laser and a cell phone camera.
https://youtu.be/LeEBn4ttZZY
Vin Gupta has the Last Word.
https://youtu.be/K03nJuHmsl8[This message has been edited by rinselberg (edited 11-21-2020).]
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Hudini
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NOV 22, 07:42 PM
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| quote | Originally posted by MidEngineManiac:
You cant live in fear....You cant.
Jake man, wake up !! There are millions of us out there who wont be ruled by fear. We are all going to die anyway, its no reason to stop living and do it while you are still breathing.
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If you don’t have good health insurance a bout with Covid at your local hospital could be very expensive. I don’t live in fear of the virus, I live in fear of owing a hospital a huge chunk of money.
For some people this is also a driving force behind their vote for Democrats.
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maryjane
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NOV 22, 11:33 PM
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Rickady88GT
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NOV 23, 07:24 AM
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Work just gave up on the N95 masks. They don't work. For the last few months they have forced us to wear a specific N95 mask the ENTIRE time we are on grounds. We were even mandated to retreat to a "hard walled room" to eat or drink. The mandate was that we do not take out mask off for ANY reason other than running to alarms.
Supposedly covid is still spreading and they gave up on the masks. Now they issue surgical masks that are CLEARLY less effective.
We will probably reach 4,000 people with positive tests and currently have 8 deaths that they blame on covid, (I have my doubts on that claim). AND I have doubts that the tests are accurate.
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maryjane
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NOV 23, 08:07 AM
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Speaking generally and to no one in particular
People are free to think whatever they want to i suppose.
1 in 10 (10%) Americans still have grave doubts that the US ever landed men on the moon in spite of overwhelming evidence that we did so.
Tens of thousands of people think lizard like aliens are walking around us in plain view but we just can't see them in spite of zero evidence to support such thought.
Thousands of people still insist the planet is flat and some have died trying to prove it. A like number also think the British crown lied about it's prisoners being sent to a far off penal colony in the South Pacific and think Australia doesn't exist and that the British govt killed all the unwanted prisoners and made up the Australia penal colony story to cover up the murders of the prisoners. (I assume they think the govt sailed them off the edge of the Earth to their deaths? )
84Bill said Don't believe everything you think[This message has been edited by maryjane (edited 11-23-2020).]
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Rickady88GT
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NOV 23, 06:32 PM
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| quote | Originally posted by maryjane:
Speaking generally and to no one in particular
People are free to think whatever they want to i suppose.
1 in 10 (10%) Americans still have grave doubts that the US ever landed men on the moon in spite of overwhelming evidence that we did so.
Tens of thousands of people think lizard like aliens are walking around us in plain view but we just can't see them in spite of zero evidence to support such thought.
Thousands of people still insist the planet is flat and some have died trying to prove it. A like number also think the British crown lied about it's prisoners being sent to a far off penal colony in the South Pacific and think Australia doesn't exist and that the British govt killed all the unwanted prisoners and made up the Australia penal colony story to cover up the murders of the prisoners. (I assume they think the govt sailed them off the edge of the Earth to their deaths? )
84Bill said Don't believe everything you think
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I am none of those people.
In fact if people want to use Synthesis as an example of a person that got covid, they should mention me as well, as an exact opposite. I have been among hundreds if not a thousand people that have tested positive for covid, over the last year. I have not even been sick with anything in a few years. I never took a flue shot, and never will. I will not take any covid shot either. If he is an example of covd, so am I. I am just the other side of the coin. I get tested once a week, and take absolutely no extra precautions than just a mask and when I can, space. I have hand sanitizer and gloves but do not use them excessively.
I never said I am a superman or immune to covid, I have said that I totally expect one of these days to get it.
The best we can do, is the best we can do. Common sense, a mask and some space works as well as anything else out there.
BTW, the infection rate out there is over 50% maybe even 60%. Literally over half the population has tested positive at some time in the last 9 months or so. Some have had 2 positive tests, and no symptoms with either test.
This covid is certainly real, certainly frustrating and certainly overblown.
Stay safe out there people.
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Notorio
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NOV 23, 07:58 PM
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Thanks for posting that article and associated links. As the forum's only laser spectroscopist (perhaps), I'd like to say that I found the technique and approach to be very creative. What is cool, with the set up being so inexpensive, is that many labs will be able to set up their own system and start to compare results when testing the same mask types, same conditions, etc. I think the 'spirit' of the team's effort was to get this method out into circulation quickly and let the process of Learning begin across many independent labs. They could have waited until they explored some of the many variables that WILL need to be explored to be able to make real conclusions (e.g. Person A vs Person B, Person A at different times, Distance from laser, how many times mask was used, etc.), but this way much more scrutiny will be brought to bear in relatively little time and We The People will certainly benefit. I say, bravo!
If you want to actually look at the live data, on the right side of figure 3B the Green trace shows the droplet count over time including the 5x repetition of a specific phrase, wearing no mask. How cool (!) that you can see when each phrase was spoken by the flood of particles! The Red trace is for speaking with a bandana, the Orange with a Cotton mask, and the Blue (too small to see) with the surgical mask. With data like that one could tentatively say that this particular Cotton (type, weave, surface treatment, etc., regrettably are variables) gets the job done pretty well and might be sufficient for areas where surgical masks are limited. Something to keep in mind when debating 'what is good enough protection?' is that we are protecting different 'risk' populations (e.g. some people are at much higher risk of having major symptoms) and we still don't know how many virus-laden particles need to be inhaled to give the virus a chance to do damage. I believe its a pretty significant number and not just one particle containing one virus.
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