High-performance masks are now available.
High-performance masks are made to a specification that significantly exceeds the filtration efficiency of industry standard N95 masks. They deliver twice the filtration efficiency, and on particles down to 10 nanometers, which exceeds NIOSH N95 requirements by a factor of ten. All masks are equipped with a robust non-springy nose wire that can be shaped to seal to your face and nose.
If you want a reusable mask that looks nice and outperforms industry standard masks, you have found it here. They look the same as the standard masks but weigh slightly more because they contain three layers.
How do these masks work? In April of 2020, six researchers decided to collect samples of numerous fabrics used to make reusable masks and measure their filtration efficiency with the same equipment used to test industry standard masks like the N95. Since the topic here is viruses, the researchers enhanced the testing setup with a particle generator producing particles down to just 10 nanometers in size, making the test exceptionally demanding. (A Covid-19 virus ranges from 80 to 100 nanometers in size.)
Cotton, flannel, silk, and other materials were tested at 1, 2, and 4 layers, and then in various combinations. The researchers expected a cotton/silk combination to perform the best because of the electrostatic interaction between the two materials. Cotton/silk showed 92 percent efficiency. Howver, the researchers discovered that cotton plus 90/10 chiffon performed even better, reaching 97 to 98 percent efficiency.
This work appears in a peer reviewed scientific paper published by the American Chemical Society here:
High-performance masks are made with an outer layer of high thread count cotton, an inner layer of 90/10 chiffon, and a comfortable inner layer of cotton muslin like the standard masks.
Get them here: https://www.ebay.com/itm/254577982386
The Covid-19 pandemic has kept me plenty busy. I apologize for not posting more often. One thing that’s kept me very busy is the making of masks, which are available on eBay.
These are top-quality masks with a comfortable muslin inner liner and outer material of high density cotton in various styles. Ear bands are comfortable 1/4-inch elastic.
Masks are equipped with a 6-inch wide padded annealed copper nose wire to conform the mask to the shape of your nose and face. This stops leakage and fogging of eyeglasses, and improves filtration effectiveness.
Please take a look at them here: https://www.ebay.com/itm/254577982386
In the interest of getting more information on the Covid-19 virus out and in easily digested form, I’ve developed three educational quizzes. Those quizzes have been added to my existing quiz web site.
The Covid-19 virus is new and much is being learned. New discoveries are made and our knowledge refined every day. There are changes in what’s known every day. In compiling information for these quizzes, I found many examples where information published a week or two ago is already obsolete. These quizzes are based on the best information I could find as of March 18, 2020.
I will do my best to keep these quizzes up to date. Please comment here on this blog post with any updates or incorrect information you may find. Ideas for additional questions or additional quizzes are welcome. In fact, this blog post exists so that you have a place to leave comments.
Click here to go to the quizzes.
Relatively new on the Shuttersparks blog are the “On This Day” posts about important historical events in science and engineering. I started these here on my main blog but I see that these posts are going to drown out everything else. So, I’ve created a new blog just for these historical posts here: https://today.shuttersparks.net/
A weather forecasting question:
For the past two months we’ve had one heat wave after another here in West Virginia. It’s been awful. High temperatures in the low 90s (Fahrenheit) with humidity giving a heat index around 100F. These conditions are 15 to 20 degrees above normal. Sometimes, it goes on for four or five days at a time without a single break. Then, there’s a one or two day break in the 80s, and then another heat wave. It’s now the middle of September, almost fall, and it continues. The forecast shows another heat wave next weekend, after the first day of fall.
An odd new thing I’ve never seen before that’s happening this summer is that forecast temperatures, both highs and lows, are consistently four or five degrees lower than the temperature actually reached. The forecast says 90, but it reaches 95. The forecast is 87, but it reaches 92. An error the other way around never happens.
As an engineer, I know that true errors are like noise and vary randomly to either side of the correct value. If the error is consistently to one side or the other, then there’s a systemic problem or calibration error.
Here’s the question. As an amateur meteorologist for over 50 years, this got me thinking. Long ago, before the powerful computer weather models of today, the historical average temperature was factored into a weather forecast. I don’t know if that’s still the case today. Might it be that I’m observing one of the effects of climate change? The climate is changing, today’s temperatures are above normal, and the historical weather data is biasing the forecast several degrees too low? Is that what’s going on?
I invite anyone who might know the answer to comment below. Thank you.
The hurricanes of 2019 have begun in earnest. For a quick review and tutorial, here’s a fun tutorial-quiz on the Maya Paradise web site:
There here are other fun tutorial-quizzes on interesting subjects here: