An animated depiction of the development of Fourier analysis. Slightly dramatized.
Tips when buying commercial air purifiers #COVIDisAirborne
#1: Always ask for the replacement filter first. That’s what to evaluate. The filter has to be white and heavily pleated for it to be a HEPA filter. If its blueish and has black carbon beads at the back, then the air purifier is no good. It indicates that it will mainly use ionization (which is performative) instead of filtration (which is needed).
ICT for the people. Certified Biodegradable