6,271 reputation
1322
bio website en.wikipedia.org/wiki/…
location United States
age 69
visits member for 2 years, 7 months
seen 10 hours ago

BS Mechanical Engr.
PhD CS(AI)
CS Prof (4yr)
Numerous consulting jobs.
15 yr at http://www.pharsight.com
Published book on CS & several articles
4 kids, 2 grand
Pilot(student)

P.S. The picture is a Beta-prime distribution. It shows the program speedup factors you can get if you see a problem twice in 2, 3, 4, and 5 samples.


Jan
22
comment Why is the Fraunhoffer Pattern the Fourier transform of the slit?
There's a pretty good explanation here.
Jan
22
comment Sailing against the wind. Is this a fair model?
That model is good, and you can use the same model to show how to go downwind faster than the wind, because the "sail" can always be turned to an angle such that the balls hit it, and the normal force has a forward component.
Jan
22
revised Simulating how comets travel with Newtonian physics
deleted 1 characters in body
Jan
21
answered Simulating how comets travel with Newtonian physics
Jan
21
answered Increasing potential in a voltage doubler
Jan
20
comment Non-determinitric flow of water stream on vertical porcelain surface
There's probably a better answer, but the water streaming down the surface has surface tension, that apparently affects it chaotically, the same way rivers meander. Flow in a straight line is unstable, because the slightest curve tends to grow on the outside.
Jan
13
comment Mirrors into Infinity
+ Nice, and you get a similar effect if you have 1) a TV camera, connected to 2) a closed-circuit TV monitor, and 3) the camera is looking at the monitor. In the 70s this was an example of electronics "freaking out".
Jan
12
revised Homopolar motor and Lorentz force
edited body
Jan
12
revised Homopolar motor and Lorentz force
added 571 characters in body
Jan
12
revised Homopolar motor and Lorentz force
added 571 characters in body
Jan
11
answered Homopolar motor and Lorentz force
Jan
11
comment Homopolar motor and Lorentz force
+ I'd never seen that before. What a nifty demonstration! If you have a wire cutting through magnetic field lines a current is induced. Then the reverse has to be true also, and that's what you're seeing.
Jan
11
comment How does the pressurization in a house's water supply allow adjustable flowrates from a tap?
I'm sure you're learned in your Ph.D. studies in fluid dynamics that pipe networks and wire networks are analogous, and an adjustable tap is just like a variable resistor.
Jan
9
comment What is so special about speed of light?
@called2voyage: Right. Thanks for the correction.
Jan
8
comment Pressure difference between 2 side of wings of aircraft
@shortstheory: This is my favorite explanation of all that.
Jan
6
comment Spontaneous motion in a wind tunnel
@GoodarzMehr: At low mach number (ignoring compresibility) conservation of mass says $\rho A_1V_1 = \rho A_2V_2$, so momentum/second in equals momentum/second out, so no net thrust. (Ignoring drag on the cone.) Jet engines work by increasing $V_2$ by expanding the gas.
Jan
6
answered Spontaneous motion in a wind tunnel
Jan
6
comment Would Beetee's electrocution plan work and kill the tributes in the lake?
If people are in the lake, they are basically conductors, being largely made of salt water, insulated only by a little layer of wet skin.
Jan
6
revised How to optically rotate images in small increments (for eyeglasses)?
added 550 characters in body
Jan
6
revised How to optically rotate images in small increments (for eyeglasses)?
added 550 characters in body