Mathew, this is not a quantitative method for nitrate determination in water or soil samples. The OP's idea of using thiosulfate is not conceptually right. Thiosulfate will not react with nitrate ion. I have a reference but the OP needs to show some effort with hints in the comments.

Poutnik, this is rather old method. Most methods use colorimetric reagents and a spectrophotometer.

Did you read the answer in the Electronics Stack Exchange? It answers your question.

Interesting, is there a reference which suggests Na2S2O3 crystals become fluorescent upon heating?

What is the exact procedure for thermal process for Na2S2O3 to convert it into a fluorescent crystal?

I have a hypothesis that your electrical discharges might be generating X-rays and X-rays are known to produce F-centers.

Also why a capacitor gives a rectangular CV is addressed here: electronics.stackexchange.com/questions/36546/…

I would suggest to study the interpretation of standard cyclic voltammograms before analyzing more complex CVs. Provide a reference whenever you take figures from somewhere so that people can understand the background of a figure more. This figure has been taken from gamry.com/application-notes/battery-research/…

It will hard to suggest or verify a quantum effect based on home experiments. Can you contact local physicists? Post more details in a physics rather than chemistry.

Ronith, the authors are making a sweeping statement. All metals can potentially form a sludge if the pH is elevated to neutralization.