7,628 reputation
1628
bio website en.wikipedia.org/wiki/…
location United States
age 70
visits member for 3 years, 2 months
seen 8 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.


Sep
26
comment How does train back draft work
+ And if the train is long, it carries air with it along the sides, lowering the pressure, so pulling in careless creatures.
Sep
25
comment Time for water levels to equalize
Pouring in the quantity of water will start a surface wave, which travels at a speed depending on the wavelength (longer = faster), and as @John said, that depends on the depth. After a couple circumnavigations, the wave will dissipate, leaving the water deeper. Not a simple problem.
Sep
24
comment Modeling wall's behaviour
It's pretty simple. The tree is going to grow, and the wall is no match for it.
Sep
24
comment Fill and drain tank (same time)
Forget ODEs and fancy theorems. $q_1 - q_2$ is the rate at which the volume of liquid increases, and the volume is height times area $A$. Unless $q_2$ is not constant.
Sep
22
answered If a body is floating in a static fluid, then the volume of the displaced fluid equal to the volume of the inmerse part of the object (proof)
Sep
17
comment Movement of a cylinder filled with water
You might simplify it by replacing the water with a pendulum suspended from the centerline of the bottle. Then the bottle could be replaced by a little "frictionless" cart on a horizontal track at the level of the bottle's center.
Sep
16
comment What is a Physically Accurate Explanation for the Kutta Condition?
I'm struggling to follow this, but I'm very impressed (which doesn't mean much).
Sep
15
comment Is voltage difference always proportional to its derivative?
You're dropping off the C (capacitance) and R (resistance) parts. Everything depends on those.
Sep
15
comment Do all elements spectrum lines fall within the visible light range?
There are ultraviolet and infrared lasers.
Sep
13
comment Does the sun “drag the solar system through space”?
The video has very pretty graphics, however it doesn't really say anything. It says heliocentric motion and helical motion are different, but the difference is in perception only.
Sep
12
revised U.S. Standard Atmosphere
added 432 characters in body
Sep
12
revised U.S. Standard Atmosphere
added 74 characters in body
Sep
12
answered U.S. Standard Atmosphere
Sep
12
comment What happens to a photon after it is absorbed by an antenna?
Receiving antennas work because the electromagnetic wave excites EMF in the a antenna wire. It makes the electrons (or charge carriers) in the wire feel force and move. In so doing, energy is removed from the wave. When a photon of light boosts an electron from one orbit to the next, it is the same thing, but on a quantum level.
Sep
11
awarded  Yearling
Sep
10
answered Why does the Metropolis algorithm allow changes even for ∆E > 0?
Sep
10
comment What are washers for?
@jnovacho: I'm under the impression that the cut in a split washer does two things: 1) apply spring pressure (so the bolt remains under tension so it won't loosen further even if it loosens a bit, and 2) to cut into the bolt head if it tries to rotate counter-clockwise. Note it is shaped to allow clockwise motion, but it resists counter-clockwise by digging in. (They are called "lock washers".)
Sep
9
answered Number of blades in a fan
Sep
8
comment A problem says : a car starts from rest and undergoes a constant acceleration. It travels 5 m in the…?
@Maher: Yes, its average speed was 5m/s, but it did not travel the whole distance at that speed. At the start of the second, its speed was zero, right? At the end of the second, its speed has to be larger than 5m/s, right? because it it was 0 at the start, and 5 at the end, its average would have to be less than 5, right? The average is 5, but the speed changes from 0 at the start to something more than 5 at the end, 10 in fact. Keep in mind that acceleration is the amount that speed changes every second. That's why it is meters per second per second.
Sep
8
answered A problem says : a car starts from rest and undergoes a constant acceleration. It travels 5 m in the…?