Nukit

@NukitToBeSure • 8,701 subscribers

Nukit at https://t.co/62nBfO0NBA (Call us "Nukit" please, other names may cause difficulty🙇🏻‍♀️)

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I'll take this as a good-faith question and try to show which parts are fairly solid science, and where things have gone completely off the rails. "So what changed?"- something did. We're in a kind of "my favorite planet is Pluto" kind of situation, but this time we can't just change what words mean in order to appease people who want what they learned in grade school to stay "true". A long-held model of how most respiratory pathogens were transmitted was upended. For over 60 years, the theory was that exhaled, coughed, and sneezed droplets took a ballistic path- like a cannonball. They arced, fell, were picked up by hands, and then faces were touched, and infection resulted. If you had a little distance and washed your hands, it was felt the risk was minimal. Around 2020 we realized that this whole model was really, really wrong. This covers it quite well: Also, this paper if you want a bit of a deep dive: This, on its own, doesn't seem like all that big a deal- ok, they don't just drop; it's an aerosol; it hangs in the air, maybe goes further, but at first glance it seems the kind of thing a minor adjustment in infection control would address. Unfortunately, not so much- and the powers that be quickly realized this, which is why the CDC did not want to acknowledge airborne transmission, and you still don't hear a lot about aerosol transmission versus droplet. It's a bigger problem than it looks like because in the same 60-year period architectural conventions have undergone massive, unprecedented changes. As various energy crises hit, the soaring ceilings, huge windows, and displacement ventilation that were implemented after the 1918–1920 flu pandemic gave way to modern, energy-efficient buildings that were nearly hermetically sealed. Every liter of fresh air in or out had to be heated or cooled depending on the season, so ventilation was minimal. High ceilings meant lower total leasable square footage- so spaces where exhalations would rise on a thermal plume, and only settle after enough time that some significant inactivation took place, were replaced with low ceilings- where exhalations were forced to drift on a lateral plane between room occupants with little space to do otherwise. Yurts, long houses, amphitheaters, castles, almost all human lodging for a very long time was fairly well ventilated- so aerosols could escape, and pathogen loads kept somewhat reasonable. In the past 60 or so years, we made sure they could not escape. Now, in a given day, an urban human will be tightly packed in a series of metal tubes and boxes, inhaling the exhalations of easily a thousand other individuals, within seconds of that breath leaving their mouth. Potent infections spread worldwide very, very fast, and are very difficult to stop- because the entire infrastructure of our lives is basically ideal for sustaining infection chains.

I'll take this as a good-faith question and try to show which parts are fairly solid science, and where things have gone completely off the rails. "So what changed?"- something did. We're in a kind of "my favorite planet is Pluto" kind of situation, but this time we can't just change what words mean in order to appease people who want what they learned in grade school to stay "true". A long-held model of how most respiratory pathogens were transmitted was upended. For over 60 years, the theory was that exhaled, coughed, and sneezed droplets took a ballistic path- like a cannonball. They arced, fell, were picked up by hands, and then faces were touched, and infection resulted. If you had a little distance and washed your hands, it was felt the risk was minimal. Around 2020 we realized that this whole model was really, really wrong. This covers it quite well: Also, this paper if you want a bit of a deep dive: This, on its own, doesn't seem like all that big a deal- ok, they don't just drop; it's an aerosol; it hangs in the air, maybe goes further, but at first glance it seems the kind of thing a minor adjustment in infection control would address. Unfortunately, not so much- and the powers that be quickly realized this, which is why the CDC did not want to acknowledge airborne transmission, and you still don't hear a lot about aerosol transmission versus droplet. It's a bigger problem than it looks like because in the same 60-year period architectural conventions have undergone massive, unprecedented changes. As various energy crises hit, the soaring ceilings, huge windows, and displacement ventilation that were implemented after the 1918–1920 flu pandemic gave way to modern, energy-efficient buildings that were nearly hermetically sealed. Every liter of fresh air in or out had to be heated or cooled depending on the season, so ventilation was minimal. High ceilings meant lower total leasable square footage- so spaces where exhalations would rise on a thermal plume, and only settle after enough time that some significant inactivation took place, were replaced with low ceilings- where exhalations were forced to drift on a lateral plane between room occupants with little space to do otherwise. Yurts, long houses, amphitheaters, castles, almost all human lodging for a very long time was fairly well ventilated- so aerosols could escape, and pathogen loads kept somewhat reasonable. In the past 60 or so years, we made sure they could not escape. Now, in a given day, an urban human will be tightly packed in a series of metal tubes and boxes, inhaling the exhalations of easily a thousand other individuals, within seconds of that breath leaving their mouth. Potent infections spread worldwide very, very fast, and are very difficult to stop- because the entire infrastructure of our lives is basically ideal for sustaining infection chains.

56,095 次观看

irene🌻 It's actually enough of a problem that we make special mahjong table air purifiers😅

irene🌻 It's actually enough of a problem that we make special mahjong table air purifiers😅

11,889 次观看

The very first batch of Nukit Lanterns off the line this month went to protect the workers themselves. We now have Far-UVC in all working and common areas. Nukit is the first company in the world to protect its workers first- so they can protect you, with safe, effective, 222nm Far-UVC light.

The very first batch of Nukit Lanterns off the line this month went to protect the workers themselves. We now have Far-UVC in all working and common areas. Nukit is the first company in the world to protect its workers first- so they can protect you, with safe, effective, 222nm Far-UVC light.

26,562 次观看

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I'll take this as a good-faith question and try to show which parts are fairly solid science, and where things have gone completely off the rails. "So what changed?"- something did. We're in a kind of "my favorite planet is Pluto" kind of situation, but this time we can't just change what words mean in order to appease people who want what they learned in grade school to stay "true". A long-held model of how most respiratory pathogens were transmitted was upended. For over 60 years, the theory was that exhaled, coughed, and sneezed droplets took a ballistic path- like a cannonball. They arced, fell, were picked up by hands, and then faces were touched, and infection resulted. If you had a little distance and washed your hands, it was felt the risk was minimal. Around 2020 we realized that this whole model was really, really wrong. This covers it quite well: Also, this paper if you want a bit of a deep dive: This, on its own, doesn't seem like all that big a deal- ok, they don't just drop; it's an aerosol; it hangs in the air, maybe goes further, but at first glance it seems the kind of thing a minor adjustment in infection control would address. Unfortunately, not so much- and the powers that be quickly realized this, which is why the CDC did not want to acknowledge airborne transmission, and you still don't hear a lot about aerosol transmission versus droplet. It's a bigger problem than it looks like because in the same 60-year period architectural conventions have undergone massive, unprecedented changes. As various energy crises hit, the soaring ceilings, huge windows, and displacement ventilation that were implemented after the 1918–1920 flu pandemic gave way to modern, energy-efficient buildings that were nearly hermetically sealed. Every liter of fresh air in or out had to be heated or cooled depending on the season, so ventilation was minimal. High ceilings meant lower total leasable square footage- so spaces where exhalations would rise on a thermal plume, and only settle after enough time that some significant inactivation took place, were replaced with low ceilings- where exhalations were forced to drift on a lateral plane between room occupants with little space to do otherwise. Yurts, long houses, amphitheaters, castles, almost all human lodging for a very long time was fairly well ventilated- so aerosols could escape, and pathogen loads kept somewhat reasonable. In the past 60 or so years, we made sure they could not escape. Now, in a given day, an urban human will be tightly packed in a series of metal tubes and boxes, inhaling the exhalations of easily a thousand other individuals, within seconds of that breath leaving their mouth. Potent infections spread worldwide very, very fast, and are very difficult to stop- because the entire infrastructure of our lives is basically ideal for sustaining infection chains.

I'll take this as a good-faith question and try to show which parts are fairly solid science, and where things have gone completely off the rails. "So what changed?"- something did. We're in a kind of "my favorite planet is Pluto" kind of situation, but this time we can't just change what words mean in order to appease people who want what they learned in grade school to stay "true". A long-held model of how most respiratory pathogens were transmitted was upended. For over 60 years, the theory was that exhaled, coughed, and sneezed droplets took a ballistic path- like a cannonball. They arced, fell, were picked up by hands, and then faces were touched, and infection resulted. If you had a little distance and washed your hands, it was felt the risk was minimal. Around 2020 we realized that this whole model was really, really wrong. This covers it quite well: Also, this paper if you want a bit of a deep dive: This, on its own, doesn't seem like all that big a deal- ok, they don't just drop; it's an aerosol; it hangs in the air, maybe goes further, but at first glance it seems the kind of thing a minor adjustment in infection control would address. Unfortunately, not so much- and the powers that be quickly realized this, which is why the CDC did not want to acknowledge airborne transmission, and you still don't hear a lot about aerosol transmission versus droplet. It's a bigger problem than it looks like because in the same 60-year period architectural conventions have undergone massive, unprecedented changes. As various energy crises hit, the soaring ceilings, huge windows, and displacement ventilation that were implemented after the 1918–1920 flu pandemic gave way to modern, energy-efficient buildings that were nearly hermetically sealed. Every liter of fresh air in or out had to be heated or cooled depending on the season, so ventilation was minimal. High ceilings meant lower total leasable square footage- so spaces where exhalations would rise on a thermal plume, and only settle after enough time that some significant inactivation took place, were replaced with low ceilings- where exhalations were forced to drift on a lateral plane between room occupants with little space to do otherwise. Yurts, long houses, amphitheaters, castles, almost all human lodging for a very long time was fairly well ventilated- so aerosols could escape, and pathogen loads kept somewhat reasonable. In the past 60 or so years, we made sure they could not escape. Now, in a given day, an urban human will be tightly packed in a series of metal tubes and boxes, inhaling the exhalations of easily a thousand other individuals, within seconds of that breath leaving their mouth. Potent infections spread worldwide very, very fast, and are very difficult to stop- because the entire infrastructure of our lives is basically ideal for sustaining infection chains.

56,095 次观看 • 1 个月前

Not only does current evidence suggest the downward ballistic-arc droplet infection model is wrong, but a large portion of exhaled bioaerosols don't just drift laterally; they actually rise on the thermal plume of warm exhaled air and body heat, then fall back into the breathing zone as they cool. This is one of the factors that extends the infectious range of bioaerosols more than intuition might indicate.

Not only does current evidence suggest the downward ballistic-arc droplet infection model is wrong, but a large portion of exhaled bioaerosols don't just drift laterally; they actually rise on the thermal plume of warm exhaled air and body heat, then fall back into the breathing zone as they cool. This is one of the factors that extends the infectious range of bioaerosols more than intuition might indicate.

199,991 次观看 • 7 个月前

This is the reality of modeling aerosols all day🤢 It's just a lot nicer not to think about that, or be like..."nah all the bioaerosols kind of just die on their own in the few seconds between when they are exhaled by someone else and I inhale them..." Because otherwise?🤮

This is the reality of modeling aerosols all day🤢 It's just a lot nicer not to think about that, or be like..."nah all the bioaerosols kind of just die on their own in the few seconds between when they are exhaled by someone else and I inhale them..." Because otherwise?🤮

53,362 次观看 • 7 个月前

Unfortunately, "protective bubbles" are almost entirely a marketing myth. Where you place an air purifier in a room in relation to yourself has almost no effect on how much protection it grants you. Air is a fluid, and fluids mix constantly with the slightest movement. It's like trying to make a "cream only" bubble in your coffee while you're stirring. Only in a room, people are the spoon. This is easy to verify with even a cheap particle counter. Take a measurement with an air purifier across the room, take a measurement with it next to you- it will be almost identical. The measurement will remain almost identical until you are a few centimeters from the air purifier's output. People feel a breeze from a purifier blowing on their face, so they think they are protected, but with the exception of some very specialized units like the Air Fanta Wear, there is almost no localized effect- it's all CADR per room, not CADR per cm away from you. Here's a CFD model with an air purifier in various locations and the relation to particle count in the breathing box (inhalation zone) of a room occupant. In short, it doesn't matter if you have a lot of CADR close to the performer, just how many CADR in the room. Big air purifiers on stage are mostly for feels and vibes. The data just does not support it. It's too much air, mixing too quickly for a localized effect. A particle counter near the performer and in the audience will show almost the same number.

Unfortunately, "protective bubbles" are almost entirely a marketing myth. Where you place an air purifier in a room in relation to yourself has almost no effect on how much protection it grants you. Air is a fluid, and fluids mix constantly with the slightest movement. It's like trying to make a "cream only" bubble in your coffee while you're stirring. Only in a room, people are the spoon. This is easy to verify with even a cheap particle counter. Take a measurement with an air purifier across the room, take a measurement with it next to you- it will be almost identical. The measurement will remain almost identical until you are a few centimeters from the air purifier's output. People feel a breeze from a purifier blowing on their face, so they think they are protected, but with the exception of some very specialized units like the Air Fanta Wear, there is almost no localized effect- it's all CADR per room, not CADR per cm away from you. Here's a CFD model with an air purifier in various locations and the relation to particle count in the breathing box (inhalation zone) of a room occupant. In short, it doesn't matter if you have a lot of CADR close to the performer, just how many CADR in the room. Big air purifiers on stage are mostly for feels and vibes. The data just does not support it. It's too much air, mixing too quickly for a localized effect. A particle counter near the performer and in the audience will show almost the same number.

13,427 次观看 • 5 个月前

Bit of fun, decided to check mask straps on my tensile strength testing machine (as one does💅🏻). Single strap attachment point load limit: 3M VFlex 9105: 1,564g Zhou Liang's mask ZM9541: 2,421g Zhou Liang's mask claimed 40n (4kg) across the whole strap (both points) so they overshot by a nice margin. That's a ton of weight on a little bit of meltblown. Any strap detachment must be some really interesting lateral loading problem with the ultrasonic welds or something like that🤔 I'm sure they'll track it down.

Bit of fun, decided to check mask straps on my tensile strength testing machine (as one does💅🏻). Single strap attachment point load limit: 3M VFlex 9105: 1,564g Zhou Liang's mask ZM9541: 2,421g Zhou Liang's mask claimed 40n (4kg) across the whole strap (both points) so they overshot by a nice margin. That's a ton of weight on a little bit of meltblown. Any strap detachment must be some really interesting lateral loading problem with the ultrasonic welds or something like that🤔 I'm sure they'll track it down.

21,004 次观看 • 1 年前

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