Saturday, February 9, 2019

Testing UV absorption eyewear and sunscreen with a deuterium light source



I use a deuterium light source to determine the absorption effectiveness of UV safety glasses and sunscreen, as well as common transparent materials.

Another interesting application of sunscreen, UV, and visual indicators:
https://www.youtube.com/watch?v=h8VJft5Xq5g

References for CIE erythema action spectrum:
http://sci-hub.tw/10.1039/C1PP05271C

https://pubs.rsc.org/en/content/articlelanding/2012/pp/c1pp05271c/unauth#!divAbstract

https://en.wikipedia.org/wiki/Deuterium_arc_lamp
https://en.wikipedia.org/wiki/Emission_spectrum#Radiation_from_molecules

http://www.aseq-instruments.com/

https://www.ebay.com/itm/Fused-quartz-glass-plate-50mm-x-50mm-x-1mm-2-pieces-Free-Shipping/123634196683

https://www.amazon.com/gp/product/B001RKFZPC/

https://www.patreon.com/AppliedScience

Monday, January 21, 2019

High-resolution screen printing demystified

A complete guide to making high-resolution screen prints with minimal tools.



Notes: When applying film emulsion to the screen, the matte surface should face the screen.  The glossy surface is the plastic backing, which is removed later, just before exposure.

The resolution test shown in the video actually indicates line width, not pitch.  So, the 1mm sample has 1mm lines and 1mm spaces.  Thus, the pitch is actually 2mm.

The Nazdar paint instructions say there is a 30 minute "induction" period that is needed for the catalyst to start working.  Nope. Just weigh out the paint and catalyst, mix, and immediately apply to the screen. Print the needed items quickly, and clean it off the screen as soon as possible.  Use disposable mixing cups / tools.  It is *messy*!

Shopping list:
Pre-stretched screen: https://www.mclogan.com/shop/aluminum-12x17-p-1173-c-293_297_379_3.html
Squeegee: https://www.mclogan.com/shop/squeegees-per-inch-durometer-p-5-c-293_297_1_4.html
Epoxy paint: https://www.mclogan.com/shop/nazdar-ade-series-epoxy-screen-ink-p-1145.html
Paint cleaner: https://www.mclogan.com/shop/mclogan-graphic-press-wash-p-156.html
Emulsion remover: https://www.mclogan.com/shop/mclogan-emulsion-remover-concentrate-p-149-c-187_42_44.html
Degreaser: https://www.atlasscreensupply.com/store/p/163-ICC-858-Stain-Remover/Degreaser-Quart.aspx
Film emulsion: https://www.atlasscreensupply.com/store/p/772-DuraCap-11-x-14.aspx
Vellum paper: https://www.amazon.com/Office-Depot-Premium-Translucent-Vellum/dp/B014SBHGMQ/


Consider using 365nm LEDs instead of fluorescent tubes for exposure.

https://www.patreon.com/AppliedScience

Monday, December 31, 2018

Behind the scenes at Applied Science: Why video? Camera gear. Shop tour.



Ask questions in the comments, and I'll answer as many as I can.

I show my video production process, answer questions about why I make videos, discuss camera gear, and do a quick shop tour.


Steve Ramsey on 10 years of YouTube: https://www.youtube.com/watch?v=uAJ01VAmAKQ

Smarter Every Day does a great job at capturing the excitement of discovery: https://www.youtube.com/watch?v=AnaASTBn_K4

https://www.patreon.com/AppliedScience

Sunday, November 18, 2018

MEMs oscillator sensitivity to helium (helium kills iPhones)



I tested the 32KHz MEMs oscillator used in some phones, and discovered that just a 2% helium environment will cause the oscillator to fail.  I also do a teardown of the MEMs device, and inspect it under the electron microscope.

iFixit blog post: https://ifixit.org/blog/11986/iphones-are-allergic-to-helium/  and vid:  https://www.youtube.com/watch?v=D0YLW6v5hrA


Original thread about MRI facility and iPhone failure on Reddit: https://www.reddit.com/r/sysadmin/comments/9mk2o7/mri_disabled_every_ios_device_in_facility/



MEMs silicon encapsulation:  http://micromachine.stanford.edu/~bongsang/pdf/Candler_2005_Transducers05_Hydrogen_diffusion_encapsulated.pdf

Applied Science on Patreon: https://www.patreon.com/AppliedScience