Monday, January 27, 2014

Cube of the Digits

There are four numbers, not counting the trivial examples of 1 and 0, where the sum of the cube of the digits equals the number itself.

153 = 13 + 53 + 33

Thank you James Randi.

Wednesday, January 22, 2014

Diesel Truck Emissions

New diesel trucks (at least big, commercial ones) need to meet certain EPA emission standards.

One way some trucks are meeting the N-oxide specification is with a Selective Catalytic Reduction (SCR) system that uses a Diesel Exhaust Fluid (DEF).  DEF is a 32.5% mixture of urea, (H2N)2,CO, and water.

The process is pretty simple.  The engine exhaust goes through a filter to remove the carbon particulates (AKA soot).  The exhaust is then sent into the SCR where it is mixed with the DEF, where the N-Oxides are converted to nitrogen, carbon dioxide, and water.

I assume that the reaction would be:
2(H2N)2CO + 4NO + O2 = 4N2 + 2CO2 + 4H2O

If this works, it would be a pretty elegant solution to nitrogen oxide emissions.  I haven’t seen any data, though.

It seems like it’s an awful lot to ask of a pretty small reaction chamber.

Friday, January 03, 2014

Winter 2013/14

This has been a rough winter so far, with twice the average snowfall and cold weather.  It was -12 when I got to work this morning.

Tomorrow we may see 30F (and we might go to the zoo) but then it will turn cold.  The high on Sunday will be 6 and a low of -18.  Monday will be brutal with a high of -12!

I don't mind the cold that much.  If you're dressed for it, it's easy to deal with.

But I'm glad I'm not going to the packer game on Sunday!