Archive for the 'programs' Category

Web port of GNU “units”

March 8, 2009

Sometimes I need to convert units on the go (you think I’m kidding?).  But, all the iPhone unit-converting programs are B.S. kid stuff.  Ergo, this here:

Step 1

Step 1

Step 2

Step 2


“Voice Reply” to emails?

October 8, 2008

What if you could send/reply-to an email with a voice message?  That would sure be handy in some situations, I think.  What if semi-literate (ie “most”) customers could do that for you?

(And how is this an opportunity to make a buck?)

Simgas, the ideal gas simulator!

October 1, 2008

This is one of those programs that’s based on 1800’s math and 1960’s technology, but has been doggedly missing.  It was driving me crazy.

It’s free and will run on MacOS, unix or even Windows with the right extra junk installed (a comment with the step-by-step details of installing said junk would be much appreciated).

Download it from

Download a non-fuzzy version of this movie from

This is super-duper-handy for solving PV=nRT, thermodynamics problems and modeling engine cycles.

It “thinks” in the metric system, but speaks whatever crazy units you like.  P = giga bars?  T = Rankine?  V = mega cubic inches?  W = horsepower-seconds?  Sure.  You can also define “mass” in moles.

It knows a bunch of gases: air, NH3 (ammonia), Ar (argon), C4H10 (butane), CO2 (carbon dioxide), CO (carbon monoxide), C2H6 (ethane), C2H4 (ethylene), He (helium), H2 (hydrogen), CH4 (methane), Ne (neon), N2 (nitrogen), C8H18 (octane), O2 (oxygen), C3H8 (propane), and H2O (steam).

You define which gas you want and then three of the four variables: P, V, mass and T.  (You can also just say “STP” to do all three of them at once.)  It solves for the fourth automatically (which is like a zillion freshman chemistry homework problems right there.)

In each step you can add to, subtract from, multiply or divide its pressure, volume or temperature adiabatically or at constant P, T or V.  You can also add or take away heat or work.

After every step it tells you what the P, V, mass and T end up being, plus the Q and W involved in that step.

This program changed my life!