Friday, October 5, 2007

Nuclear Laptops.

I use stumbleupon and lately for 5 times i've been stumbling onto webpages about "laptop batteries that lasts 30 years". This bullshit is getting annoying. There's no way these batteries going to be public.

Several quotes from article:
"We have a non-thermal reactions so there is also no risk of over-heating"
Non-thermal reaction. Yeach.
Laptop consumes over 50W of power. Quick search shows that maximal possible electrical conversion efficiency for betavoitaics is around 25% which means there needs to be 200W of total power, 25% of which, that is 50W is converted to electricity (so in laptop you have 150W coming as heat directly from the battery, and 50W of heat coming from electronics). Surely such laptops are going to be very hot product.

"when the battery runs out of power it is non-toxic"
Radioactive decay doesn't work like emptying bathtub. After time of half-life, there's half of radioactive material, after two times of halflife there is quarter (and so on). Suppose battery is 2x more powerful than what your laptop needs. It means that when battery no longer could power your laptop, there is still a half of radioactive material remaining in the battery (actually battery is going to die earlier than that because of degradation of semiconductors due to radiation, but i digress).
Now, on the toxicity. Beta particles don't travel much distance in materials The radioactive material could be made into some mostly insoluble form to prevent it from contaminating environment and being ingested. I'm not sure about how insoluble it could be made. All i know is, it takes very little radioactive material to poison a human, comparing to amounts of material producing such power output levels.

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