Thursday, April 10, 2014

Electron beam control in a scanning electron microscope

I describe electron beam optics and deflection as they are employed in scanning electron microscopy.

http://web.jfet.org/vclk/ - Deflection amplifier

http://www.johngineer.com/blog/?p=648 - CRT Christmas tree

http://www.fei.com/ - FEI Company


Sunday, March 23, 2014

Vacuum and pressure frying fruits and vegetables

I talk about the technique of varying the pressure in a fryer to change how it cooks food.  Lower temperatures and pressures allow the food to be dried, and infused with oil without scorching or browning it. Higher temperatures and pressures keep the interior of the food moist while darkening the exterior. Fruits and vegetables are generally more appealing when vacuum fried, and chicken is arguably better when pressure fried.


Sunday, March 9, 2014

How a Mass Flow Controller works

I bought a couple mass flow controllers from eBay to improve the process control of my sputtering chamber.  These MFCs are much better suited than a needle valve and rotameter (manual flowmeter).


Monday, March 3, 2014

pH indicating soap bubbles - more work needed

I thought it would be cool to have a colored soap bubble that responded to changes in pH.  I concentrated some phenol red (pH indicator), and mixed it with commercial bubble solution.  Unfortunately, it was not dense enough to actually show its color. While investigating this, I noticed that normal soap bubbles lose their color as they become thinner (due to evaporation) and eventually burst.  I tried to get footage of this color loss, but the bubble will not stay in the same place!  I started to develop a method to partially fill the bubble with helium to make it neutrally buoyant.


Monday, February 24, 2014

How a breathalyzer works (alcohol sensor)

I teardown a commercial, handheld breathalyzer and discuss how it works, then test a standalone ethanol sensor.
http://www.seeedstudio.com/depot/images/product/MQ303A.pdf
http://www.kosmodrom.com.ua/pdf/MQ303A.pdf
http://www.sparkfun.com/products/8880

http://www-personal.umich.edu/~mswool/publications/Gas_Sensors_preprints.pd.pdf