DIY mass spectrometer measures potassium in dietary salt substitute

How to build and operate a simple mass spectrometer. Please ask questions in the comments, as always.

Scientific American article: https://www.scientificamerican.com/article/the-amateur-scientist-1970-07/  $7.99 is a good value for the entire back issue in plain PDF format, and an example of a publisher being reasonable.   I'm happy to support this.

Original Dewdney paper: https://sci-hub.tw/https://doi.org/10.1119/1.1969211

https://en.wikipedia.org/wiki/Isotopes_of_potassium
https://en.wikipedia.org/wiki/Ionization_energy
https://en.wikipedia.org/wiki/Thermal_ionization
https://en.wikipedia.org/wiki/Gyroradius

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https://www.youtube.com/watch?v=ezME4_xMMnk

Teardown of a "date back" or "data back" camera and description of how it works: A micro LCD projector with incandescent light bulb! https://www.patreon.com/AppliedScience

Cryogenic treatment of drill bits: tested 2X lifetime and microstructure analysis

I bought some HSS stub drills, and treated half of them with liquid nitrogen, which improved their wear resistance dramatically. I also look at the change in microstructure with an electron microscope.

Performance of cryogenically treated M35 HSS drills - http://sci-hub.tw/10.1007/s00170-011-3616-8
Performance of cryogenically treated HSS tools - http://sci-hub.tw/10.1016/j.wear.2006.01.017
Effects of Cryogenic Treatment on the Strength
Properties - http://sci-hub.tw/10.1088/1757-899X/229/1/012014

LN2 generator video: https://www.youtube.com/watch?v=7PWESWqhD8s
Heat treatment of steel video: https://www.youtube.com/watch?v=ulfCxDsVTWo

Source of drill bits: https://www.mcmaster.com/catalog/125/2508

Temperature logger (discontinued, unfortunately): https://www.adafruit.com/product/3081

3M fine polishing pads: https://www.amazon.com/Tri-M-Ite-Polishing-Abrasive-Assorted-Sheets/dp/B07CP9CCH4/

Delorean patent on cryogenic torsion bar: https://patents.google.com/patent/US4378658

Steel grain structure inspection, and overall great channel for material analysis: https://www.youtube.com/watch?v=UuHofNW40Yw

Steel grain structure video: https://www.youtube.com/watch?v=0SIr2sBHxA4


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

UV laser creates disappearing ink in normal printer paper

Ordinary printer paper is darkened by a high power UV laser, and then the affected area disappears in four minutes!  This is caused by fluorescent brightening agents that are added to printer paper, which are temporarily overloaded by the intense UV light. It seems that oxygen plays a role in this, as hydrogen peroxide applied to the marks cause them to disappear instantly, and prevent them from being formed again by the laser. Performing the experiment in argon appears to slow the disappearing ink effect.

https://en.wikipedia.org/wiki/(E)-Stilbene
http://abchemitrans.com/dokumenty/Brochure_OPTICAL_BRIGHTENERS.pdf
https://www.tandfonline.com/doi/abs/10.1080/19440049.2014.934302?mobileUi=0&journalCode=tfac20
https://patents.google.com/patent/US20140339462A1


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"Bouncy" sulfur hexafluoride gas in tennis balls?

Testing myths about gas inside tennis balls.
Note:  I should have added that all of the gases tested would have the same bounce height in a perfect no-loss system.  The reason that SF6 bounces higher is because it heats less during compression, lowering the amount of possible thermal loss.  Argon heats more during compression, and can lose more energy because of thermal transfer from the gas into the cylinder walls, where it is not restored upon decompression.  Things are more complex in a tennis ball, though:  Most of the losses are in the rubber shell, and not in the thermal dissipation of the fill gas.  It's hard to estimate, but I'd say that the highest fill pressure, with a high-gamma gas would prove to be the most bouncy since it would cause the rubber shell to deform the least.  The amount of compression in a tennis ball is very low, and any effect due to the gamma of the gas will be extremely small.  Fill pressure will have a dramatically bigger effect.

Google drive link : https://drive.google.com/open?id=10gktbl7YQve5IKNAak1L0wIS_g_4BVEW
 Nike Air: https://news.nike.com/news/nike-air-max-sustainability

EPA SF6 use: https://www.epa.gov/sites/production/files/2016-02/documents/conf00_smythe_paper.pdf

100 kg load cell: https://www.amazon.com/gp/product/B077YHNNCP/
Instrumentation amplifier: https://www.ebay.com/itm/INA114-Instrumentation-Amplifier-Module-1000-Times-Gain-Adjustable-Single-Supply/272973857983

SF6 on eBay:  https://www.ebay.com/itm/Sulfur-Hexafluoride-SF6-18-lb-Tank-New-full-cylinder-Insulating-Gas-SALE/283464688564

Tennis ball patent: https://patents.google.com/patent/US4358111

SF6 data sheet: https://npeinc.com/manuals/General%20Electric/GEBK-IBvendor/ALLIED%20CHEMICAL.PDF

SF6 worldwide usage: https://www.ipcc-nggip.iges.or.jp/public/gp/bgp/3_5_SF6_Electrical_Equipment_Other_Uses.pdf


General adiabatic resources:
http://rogercortesi.com/ideas/public/gasspring.html 
https://arxiv.org/pdf/1708.01282.pdf
http://isjos.org/JoP/vol1/Papers/JoPv1i1-2Tennis.pdf
http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/souspe3.html

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