Self-cleaning water bottles working mechanism!
Hey friends, Happy Wednesday!
Answer to the question I posed last week
Last week, I asked how often a sine curve signal should be sampled so it can be retraced without losing information. And if it has a name? If the frequency of a sine curve is F Hz, then the sampling should be done at least more than 2*F Hz. And this is called the Nyquist frequency. Refer to my previous newsletter to understand the sampling of signals.
The concept we’ll cover this week to understand how self-cleaning water bottles work is UV radiation. Several gadgets that involve any kind of filtration use this technology in some way or another. I aim to write my newsletter issues in a way one can follow them while traveling on a bus, having a coffee, waiting for your food, etc. Let’s jump in!
Why are UV radiations so important in gadgets, and how do they work?
Ultraviolet rays are used to destroy bacteria, viruses, and other impurities present in water. UV disinfection technology destroys the DNA of microorganisms, leaving them dead and unable to grow further. UV disinfection technology can be used for drinking water disinfection, process water disinfection, and wastewater disinfection, the food & beverage industry, cosmetics, pharmaceutical & healthcare products, swimming pools, and surface disinfection.
But the wavelength of UV light that effectively kills them could be different, and here is how we test them. UV light within a range of wavelengths from about 210 nm to 365 nm is tested in a self-cleaning water bottle for example. UV LEDs are used to illuminate at different wavelengths - some peak at about 280 nm and a few others at 320 nm for example. By having multiple UV wavelength peaks, biological impurities with different response characteristics can be determined.
For example, viruses may respond to a first UV LED characterized by a first UV frequency, the bacteria may respond to a second UV LED characterized by a second UV LED frequency. Pathogens exposed to the first UV frequency light may reflect the UV frequency light, and the other impurities exposed to the second UV frequency may fluoresce.
Significance of UVC type of Ultraviolet light
There are different types of ultraviolet light based on wavelength. UVA rays have the longest wavelength (320 nm - 400 nm), followed by UVB (280 nm - 320 nm) and then finally, UVC (200 nm - 280nm). While UVA and UVB rays are transmitted through the atmosphere, all UVC and some UVB rays are absorbed by the Earth’s ozone layer. So, most of the UV rays you come in contact with are UVA with a small amount of UVB. UVC radiation is the highest energy portion of the UV radiation spectrum.
UVC radiation from the sun does not reach the earth’s surface because it is blocked by the ozone layer in the atmosphere. Thus, the only way that humans can be exposed to UVC radiation is from an artificial source like a lamp or laser. UVC radiation can cause severe burns of the skin and eye injuries.
UVC is ultraviolet rays at around 250nm wavelength are used in a self-cleaning water bottle to kill most of the impurities - Like viruses and bacteria. The light travels in a straight line but is designed to reflect within the bottle. Read the blog post in the link below to learn how they work!
Question of the week
What are some other ways by which filtration and cleaning are done apart from using UV radiation? There are countless gadgets that use UVC for disinfection. Can you think of some? Share your thoughts by replying to this email, and we can have a discussion. I’ll answer this in next week’s issue. Thanks for replying to my emails and engaging with my content!
Blog posts
My blog post S1E6 on Self-cleaning water bottles is out! Read it here, happy learning!
Learn how self-cleaning water bottles work
I’m thinking of writing about fall detection algorithm in a fitness watch for the next episode S1E7. Also, let me know if you’d like to read about a specific gadget/device.
Have a nice rest of the week, and take care!
Until next Wednesday,
Chendur
