[ARC5] AB5S Kung Flu Update, 13 June - source?

Richard Knoppow 1oldlens1 at ix.netcom.com
Sun Jun 14 18:50:59 EDT 2020 

    May be California, Los Angeles stores have the same rule.

On 6/14/2020 1:48 PM, Scott Robinson wrote:
> Atmy local supermarket for sure, and, I think, at most other 
> other stores as well, the rule is: no mask, no entry. This may 
> be local (Marin County, California) regulation, but seems like 
> a good idea to me.
>
> /scott robinson
>
> On 6/14/20 1:42 PM, Bill Cromwell wrote:
>> Hi,
>>
>> The differences between N95 and my bandanna are irrelevant 
>> since I cannot get even one N95 mask. It won't work with my 
>> beard anyway and the bandanna covers most of my beard. All due 
>> respect to Ken, I will do the best I can with what I actually 
>> have available. At the local store we call maskless people 
>> "nudists". We stay as far from them as we can.
>>
>> 73,
>>
>> Bill  KU8H
>>
>> bark less - wag more
>>
>> On 6/14/20 4:31 PM, Michael Hanz wrote:
>>> Excellent question, but it doesn't appear to be addressed in 
>>> this study, Richard.  I think they were simply trying to get 
>>> some sense of the magnitude of the problem.  Some commercial 
>>> masks have numbers associated with them (like the N95 masks), 
>>> but the sheer variety of potential materials for home made 
>>> masks would make that second step a time consuming task, so I 
>>> suspect the next phase won't come as quickly.  At least the 
>>> droplet size and density has some specificity that could be 
>>> compared with typical mask materials and numbers of layers.
>>>
>>> On 6/14/2020 3:04 PM, Richard Knoppow wrote:
>>>> Were there any tests of speakers using conventional masks? 
>>>> The difference made by the masks would be important.
>>>>
>>>> On 6/14/2020 11:54 AM, Michael Hanz wrote:
>>>>> That pretty much aligns with my view, Scott, with the 
>>>>> addition of information from an interesting study about 
>>>>> aerosols produced by simply "normal" talking, reported at 
>>>>> https://www.nytimes.com/2020/05/14/health/coronavirus-infections.html 
>>>>> (The National Academy of Sciences detailed report is at 
>>>>> https://www.pnas.org/content/117/22/11875 ).
>>>>>
>>>>> The gist of the article was:
>>>>> "To see how many droplets are produced during normal 
>>>>> conversation, researchers at the National Institute of 
>>>>> Diabetes and Digestive and Kidney Diseases and the 
>>>>> University of Pennsylvania, who study the kinetics of 
>>>>> biological molecules inside the human body, asked 
>>>>> volunteers to repeat the words “stay healthy” several 
>>>>> times. While the participants spoke into the open end of a 
>>>>> cardboard box, the researchers illuminated its inside with 
>>>>> green lasers, and tracked bursts of droplets produced by 
>>>>> the speaker.
>>>>>
>>>>> The laser scans showed that about 2,600 small droplets were 
>>>>> produced _per second_ while talking. When researchers 
>>>>> projected the amount and size of droplets produced at 
>>>>> different volumes based on previous studies, they found 
>>>>> that speaking louder could generate larger droplets, as 
>>>>> well as greater quantities of them.
>>>>>
>>>>> Although the scientists did not record speech droplets 
>>>>> produced by people who were sick, previous studies have 
>>>>> calculated exactly how much coronavirus genetic material 
>>>>> can be found in oral fluids in the average patient.  Based 
>>>>> on this knowledge, the researchers estimated that a single 
>>>>> minute of loud speaking could generate at least 1,000 
>>>>> virus-containing droplets."
>>>>>
>>>>> Here's a picture of the test setup:
>>>>>
>>>>>
>>>>> That makes it even more than a courtesy to wear a mask, 
>>>>> especially since most coronavirus spreaders aren't even 
>>>>> aware when they are in the early stages of their 
>>>>> infection.  The cloth masks are indeed not perfect, but 
>>>>> they are only intended to reduce the frequency of the much 
>>>>> larger droplets, not the much smaller virus which is 
>>>>> attached to them.
>>>>>
>>>>> - Mike  KC4TOS
>>>>>
>>>>>
>>>>> On 6/14/2020 2:00 PM, Scott Johnson wrote:
>>>>>> I consider the primary reason for masks, or bandanas, or 
>>>>>> whatever, not to
>>>>>> protect yourself, but to protect other from you.  It is a 
>>>>>> courtesy, if you
>>>>>> sneeze, cough, or slobber when you talk, it effectively 
>>>>>> prevents the aerosol
>>>>>> from going further than the fabric.  Not wearing anything 
>>>>>> in proximity to
>>>>>> the public identifies one as  careless and reckless.  If 
>>>>>> you are in a high
>>>>>> risk group, and truly worried about your own safety, then 
>>>>>> you shouldn't be
>>>>>> exposing yourself needlessly.  I have heard so many 
>>>>>> opinions, some that are
>>>>>> diametrically opposed, and all from supposed experts. 
>>>>>> Don't care to hear
>>>>>> any more. Common sense coupled with common decency should 
>>>>>> prevail. BTW, one
>>>>>> of my engineers did a CFD model in Solidworks of a sneeze 
>>>>>> in a room with
>>>>>> closed loop HVAC.  It propogates and dissipates pretty 
>>>>>> much like a fart.
>>>>>>
>>>>>> Scott V. Johnson W7SVJ
>>>>>> 5111 E. Sharon Dr.
>>>>>> Scottsdale, AZ 85254-3636
>>>>>> H (602) 953-5779
>>>>>> C (480) 550-2358
>>>>>> scottjohnson1 at cox.net
>>>>>> scott.johnson at ieee.org
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From:arc5-bounces at mailman.qth.net 
>>>>>> <arc5-bounces at mailman.qth.net>  On Behalf
>>>>>> Of Hubert Miller
>>>>>> Sent: Saturday, June 13, 2020 11:21 PM
>>>>>> To:arc5 at mailman.qth.net
>>>>>> Subject: Re: [ARC5] AB5S Kung Flu Update, 13 June - source?
>>>>>>
>>>>>> Generally good advice, but I question the non-cough 
>>>>>> non-sneeze 26 foot
>>>>>> business, no matter what your doctor said.
>>>>>> I have read several articles in the New York Times 
>>>>>> precisely on this
>>>>>> question, and those articles are well informed, very well 
>>>>>> informed,
>>>>>> frequently updated. Ask your doctor his source for his 
>>>>>> information. I recall
>>>>>> now they also had an article comparing actual 
>>>>>> effectiveness of different
>>>>>> kinds of masks, both homemade and commercial, and gave 
>>>>>> actual numbers
>>>>>> compared to N95, and what thickness required even with 
>>>>>> homemade.
>>>>>> Also, masks are dry material, so what is your informed 
>>>>>> reckoning of how long
>>>>>> virus lives on them ?
>>>>>> As for health professionals dying despite masks, well, you 
>>>>>> would have to
>>>>>> know the extent of their exposure and their full suiting 
>>>>>> equipment to assign
>>>>>> this to mask inefficiency.
>>>>>> Don't forget UV exposure either, to kill virus. These 
>>>>>> parameters apply
>>>>>> outside also.
>>>>>> I found Elderberry anything to be pretty much sold out 
>>>>>> locally last time I
>>>>>> shopped, but I'll take another look in the next days.
>>>>>> -Hue Miller
>>>>>>
>>>>>>
>>>>>>
>>>>>>
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>>>>>
>>>>> -- 
>>>>> Michael Hanz - KC4TOS
>>>>>
>>>>> ______________________________________________________________
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>>>
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-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL

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