Welcome to my musings on whatever topic catches my eye, plus stories, recipes, handyman tips, welding, photography, and what have you. Oh, and analog/digital hardware design, and software. Please comment on the blog post so everyone who visits can see your comments.
As you probably know, I’m making hygienic masks — both standard type and high-performance masks that exceed N95 masks in filtration efficiency, especially on very small particles down to 10 nanometers.
Obtaining high quality fabric has been challenging for the past 2-1/2 months. I have lots of other fabrics with nice patterns but I prefer not to make masks out of flimsy material. I might eventually use those for applique designs on top of robust fabric. But the good stuff has started to arrive, finally. Hurray!
Right now I’m focusing on producing masks with patriotic USA themes for upcoming Independence Day. However, a number of long-awaited top quality fabrics have arrived. Below are some photos. If you fancy any of those below, please let me know and I’ll make masks using those fabrics first.
I haven’t named them yet, so I’ll just number them for the time being. A mask or ruler is included in the photos for scale.
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:
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.
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.