Recent content by johnsonb.engr

  1. J

    I Dissolution of a metal sphere

    Hello Simon, Thank you very much for your response. Maybe I am not fully understanding your answer. The A, I am trying to find is not the surface area of the sphere but rather a constant found in the solution to dm/dt = -c*s(m) = -c*4πi*(3m/(4πi*ρ)^(2/3) (equation 1) where the solution to...
  2. J

    I Dissolution of a metal sphere

    Hello All I could get some help I would greatly appreciate it. I am trying to figure how to calculate the dissolution time of sphere undergoing constant corrosion at a rate of corrosion. Through a little google-fu, I found an article which gives me the solution (...
  3. J

    Tungsten coated molybdenum powder

    Hello Everybody, I would greatly appreciated your help. I have been working this problems for the past couple hours and can't seem to find the answer. I tried Google, and opening up my old textbooks but to no avail. I could really use some help. I have sample of tungsten coated...
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    Schools Chances of Getting into UCSB with 3.21 GPA

    Thank you ever much for the reply physics girl phd. You have helped me avoid several errors in witting my letter. Thank you again. I am off to write that letter. ps. I have one more questions if you have time to answer it. Growing up I have severe learning disabilities, to the point where...
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    Schools Chances of Getting into UCSB with 3.21 GPA

    Thanks for the advice. Thank you for being completely honest. Do you think I have a chance if I can do well on my GRE's. Do you have any other recommendations on UC schools that have a good materials program that i might be able to get into. I think my GPA, being only 3.21 will hinder me from...
  6. J

    Schools Chances of Getting into UCSB with 3.21 GPA

    Not sure if this question belongs here, but i have a question about getting into one of the following, UCSB, UCSD, UCB, or cal tech. My first choice would be UCSB. I am currently and mechanical engineering major at sdsu. My cumulative GPA is 3.21, I am in tau beta pi (the honors society), am...
  7. J

    Water invert house, fill it fail?

    Hello Every one, I am trying to design water vessel which shaped like an inverted house (i.e. a rectangle attached to a triangle). I want to find the pressure and force distribution along the walls of tank (it is open to atmosphere). I have tried solving this in excel using the equation...
  8. J

    Transient heat transfer problem in cylinderical coordinates

    Ok thanks for the help. I am having a problem find the currect solutions to this problem, from a previous post of PF https://www.physicsforums.com/archive/index.php/t-204570.html i found that u(r,z) = u_0 \cdot \sum_{n=1}^{\infty}\frac{sinh(\lambda_n z) \cdot J_0(\lambda_n r)}{\lambda_n...
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    Transient heat transfer problem in cylinderical coordinates

    ok thank you very much for the reply. I looked up the conduction equation for spherical eq and got. Can u understand this, i don't really known how to work with latex, but i can reenter it needed. 1/r(d/dr)(kr(dT/dr)) + 1/r^2(d/dO)(k(dT/dO) + d/dz(kdT/dz) + q = pc(dT/dt) once again the...
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    Transient heat transfer problem in cylinderical coordinates

    I know my last post was a little long winded, but i here a summary of my problem. I have to use separation of variables to find the Tx in a cylinder which is heated from the a whole along its axis and the out side of the cylinder is completely insulated. In class we look at bessel function...
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    Transient heat transfer problem in cylinderical coordinates

    y Could some one please help me. My professor for a lower level programming class (in labview) has given the class the following assignment. This is not a heat transfer class and he has not spoken/taugh us anything related to heat transfer. He emailed us a few pages from a heat transfer...
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    Learn LabVIEW: Books & Tutorials for Beginners

    Labview help! Hello, everybody. I am not sure if this is the right spot for my question because labview is a ME not CS Does anyone have any good recomdations of books or online tutorial which can help me learn this software. I am currently taking a class in it, but the class has no text...
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