Julian W

Software Developer (Java, C/C++, Monkey-c, NXC), Electronics, Slow Runner, Technology Enthusiast

[PCBWay @PCBWayOfficial]

Do you like the PCB ruler in purple? Join us #FreeGiftFriday

[Julian W @waldjm]

@PCBWayOfficial Sounds useful! #freegiftfriday

[David Howard @Used_For_Glue]

This really isn't how y-axes work

[Julian W @waldjm]

@omnialnchristo Many years ago, I woke in the middle of the night to a full recital by a nightingale in the garden. Lasted 5 to 10 minutes - a really beautiful experience.

[Hampshire County Council @hantsconnect]

New Coronavirus Hampshire Helpline

For frail or vulnerable people who need urgent assistance with essential food or household supplies, collection of medication, or who are at risk of loneliness.

☎️0333 370 4000

https://t.co/S389ydkmti

#HantsHelp4Vulnerable #Hereforyou

[OCDS | Secular Carmelites | London Region @ocdslondon]

This is such a great initiative - thank you 😊🙏@OfReligious @carmelnunsgb @SisterWalburga @digitalnun @UKReligiousLife @ukvocation @DomSrStJoseph @CatholicVoices @BroRichard @EvangelisationW @ccfsouthwark @londonjesuit @RC_Southwark @MaryvaleInst

[Nigel Farage @Nigel_Farage]

Health Secretary Matt Hancock says we are going to build diagnostic capability never before seen in this country. We hear this every week and no longer believe him.

[Julian W @waldjm]

@eevblog I assume you have heard about this from WA

https://t.co/1XEbDOL7tD

[Claire Fox @Fox_Claire]

Very disappointed Raab didn't use opportunity of 2 good questions to reign in police over-zealousnes & enforcement far beyond official rules. We can tolerate lockdown but if politicians allow draconian over-reach, can undermine whole strategy; worrying threat to liberty long-term

[Lord Mayor of Southampton @TheSotonMayor]

The Chinese Association have donated 100 c19 test kits to Southampton CCG. These will be used on NHS staff which may allow them to get back to work faster. I received the tests from Dr Li and handed them over. Thank you very much.

[Naomi Wu 机械妖姬 @RealSexyCyborg]

DIY fucking around with respiration- diving helmets, rebreathers, all that, is right up there with DIY manned flight for huge body count. You plan for, teach and illustrate the absolute worst-case scenario. If you are stupid enough to downplay that in my mentions, expect a block.

[Naomi Wu 机械妖姬 @RealSexyCyborg]

So if you are a journalist- desperately hunting for clickbait with the usual sociopathic glee of your profession, kindly stop signal-boosting untested, unusable "3D printed face masks". People are wasting time and resources because you are misleading them that these are viable.

[Naomi Wu 机械妖姬 @RealSexyCyborg]

So far none of these "3D printed N95 masks" are even remotely airtight so this hasn't been an issue- people are just sucking air in and out the sides, very little is going through the filter medium, but with a heavily customized mask you could get a seal good enough to kill you.

[Naomi Wu 机械妖姬 @RealSexyCyborg]

One arm holds the mask against your face. Raise one arm above your head. If your arm drops- your buddy yanks the mask completely off and put you into recovery position.

[Naomi Wu 机械妖姬 @RealSexyCyborg]

So first off- if you are really committed to perfecting your 3D printed N95 masks, you need to have a buddy when you test it, sit cross-legged on carpet (because an uncontrolled fall from standing or even sitting could result in a head impact that will likely kill you).

[Naomi Wu 机械妖姬 @RealSexyCyborg]

That's why industrial respirators have a check valve for exhalation- to avoid that CO2 build up. We can't have a check valve in a healthcare setting since it would blow droplets all over the place. We need to filter inhalation, and exhalation- without CO2 buildup.

[Naomi Wu 机械妖姬 @RealSexyCyborg]

This results in CO2 buildup. After about 30 minutes your plastic mask, if actually airtight and strapped securely to your face will, before you can take it off, kill you- very peacefully. You'll just slump over and go to sleep, but you'll still be dead.

[Naomi Wu 机械妖姬 @RealSexyCyborg]

N95 mask material has a fair amount of air resistance- so the masks have a large surface area, trying to breathe through a little disk of N95 material is like trying to breathe through a straw. But it gets worse- you have to try and exhale through the same little disk of material

[Naomi Wu 机械妖姬 @RealSexyCyborg]

Part 2- Why 3D printed N95 masks are not a thing.

N95 certification requires an airtight fit. If you are sucking in, or blowing out air from the sides of your 3D printed cosplay prop, viruses carrying droplets are going all over the place- it's not N95.