Astronuc

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Showing Visitor Messages 1 to 10 of 32
1. Apr2-13 05:34 PM
mfb
Just a quick comment about the Alexa value: Alexa calculates a rank based on the (estimated) page impressions. google.com has the most and gets rank 1, wikipedia.org has rank 7, and physicsforums.com has a rank of 12,802. There are no absolute values of page impressions available.
My guess would be something around 100k/day.
2. Dec30-12 05:10 PM
ra_forever8
Consider a long, thin, uniform rod of constant cross-section whose temperature distribution is θ(x,t), surrounded by an atmosphere of constant uniform temperature θ0. The sides of the rod are not insulated so that heat is lost from the longitudinal surface at a rate h(θ(x,t)- θ0) per unit length, for some constant h. Derive the equation which describes the temperature distribution in the rod and show that it can be written

∂φ/∂t=k/ρc (∂^2 φ)/(∂x^2 ) - (h/ρAc) φ

where φ(x,t) = (θ(x,t)- θ0), k is the thermal conductivity, ρ the density , c the thermal capacity and A the cross-sectional area of the rod.
Such a rod of length l is initially maintained at a constant temperature θ1. Both ends of the rod are then brought to and maintained at temperature θ0 and the rod is surrounded by an atmosphere at temperature θ0. Show that the temperature distribution in the rod at any subsequent time t has the form
θ(x,t)= θ_0+∑_(n=1)^∞▒〖B_n e^(-k/ρc ((n^2 π^2)/l^2 +h/KA)t ) Sin (nπx/l)〗

find Bn.
3. Nov14-12 09:33 PM
The Prince
Hello Astronuc,

Kindly answer my question "MCNP code". I need your guidance as I am new in MCNP
4. Oct10-12 05:35 PM
nukapprentice
I sent you a private message, thanks.
5. Sep30-12 04:34 PM
BrianSteps
Hello Astronuc, I saw you were a Nuclear Engineer. As I am really interested in Nuclear Engineering I would like to know where to study Nuclear Engineering (I'm from Europe), so did you study it in USA ?
6. Sep16-12 12:47 PM
KayakGuy
This Physics Forum website seems to be a total BUST. I believe that I explained in my original post the situation well enough for a grade school child to visualize. I never asked for specifics, therefore no math was required. Any engineer that knows anything about fluid dynamics should have been able to easily visualize my question and give a quick answer. In the time I've waited for a response from this website, I've been able to figure a solution to the problem on my own through use of physical experimentation to confirm my personal hypothesis...I am sincerely disappointed at the lack of attention shown toward what should have been a simple question. Berkeman's lack of attention to my post, and his rudeness...Deleting my first post because of my mistake with "multiple" postings to other forums. Then after re-posting my question, he moved it to one forum (ME) where it sat unanswered and never moved it again. There seems to be poor oversight, if any toward the Mentors.
7. Aug3-12 11:35 PM
jim hardy
thanks for the guidance and help you have given. it is comforting to have you guys on the bridge.

old jim
8. Jun15-12 02:26 PM
rduarte
Awesome beard!!!

Had to say that, sorry.
9. Jun13-12 01:18 AM
Coxy1234
Thanks for the help, Astro! You're the best!
10. Jun5-12 08:37 AM
Kballer
Sir!
I have just been reviewing your posts on fluid mechanics. I am a stranger from the other side of the world who has a fluids exam tomorrow and is stumped on this question! Please if you can answer it for me that'd be great.
Why, if the flow is fully developed, is there still pressure drop with friction if the flow can be said to be in steady state i.e. shear stress = pressure gradient force?

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Married, 2 kids (2 adult children), academic background - nuclear/astrophysics, then nuclear engineering, materials science and engineering, some electrical and aerospace engineering.
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Getting the 'right' answer is important, but understanding how to solve the problem (i.e. how you get the right answer) is just as important, if not more so.
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