Search results

  1. D

    Submarine Modeling

    it would be very cool if you solve that with integrals, but its a lot more than you need, really
  2. D

    Thermodynamics Help

    I used that book for thermo 2, and I hated it. Try using Wark's or Cengel's. If you want a more theoretical approach, you can go for Callen's "Thermodynamics and an introduction to thermostatistics"
  3. D

    Can anyone check this identity please?

    yes, actually, I was trying to take the curl of the Navier-Stokes equation, to get the vorticity equation, a problem in Bird's transport phenomena, the book asks you to deduce it in two forms, the first one is the one I have already, the second one involves the Levi-Civita symbol and I'm...
  4. D

    Can anyone check this identity please?

    I know now, thank you. Actually that "identity" es not true unless Div(v)=0, because another term is missing. However that fits perfectly since im working with fluid mechanics. Thanks again!
  5. D

    Can anyone check this identity please?

    I finally found it, looks like I was missing another term in the right side v(Div(v)), altough this is 0 in my case because im working with fluid dynamics. Now everything makes perfect sense, thanks anyway
  6. D

    Can anyone check this identity please?

    is this identity true? V is a vector, so VV is a second order tensor I have tried to prove this but the components of the tensor appear always as operands of the nabla. Thanks! Div(VV)=v.(Grad(V))
  7. D

    Can anyone check this identity please?

    1. Homework Statement I just want to check if this identity is true, since I have not found it anywhere, can anyone help me? v is a vector (and that nu is supposed to be a v too)
  8. D

    Nucleophilicity of an aldehyde

    Yes, actually I want to do the molecule attached, as you can see, it is not an activated system, thats why I thought I could use aromatic nucleophilic substitution
  9. D

    Fluid mechanics book for ChemE

    Hi! Im a student in chemical engineering and I would like some recommendation for a fluid mechanics book, I've been using Bird's Transport Phenomena but it seems to be a bit difficult to follow it, as it skips a lot of steps.
  10. D

    Nucleophilicity of an aldehyde

    Does anyone know if an aldehyde, specifically, acetaldehyde behaves as a good nucleophile? I'm trying to insert an aldehyde in an aromatic compound through an aromatic nucleophilic substitution, any information or source to pKa data would also be appreciated, thanks!
  11. D

    Synthesis of an organic compound

    1. Homework Statement I've been asked to explain how would I synthesize an organic compound, its structure is attached as an image (first attachment) , could you help me figure it out? I'm supposed to start from benzene 3. The Attempt at a Solution So far, Ive got a big part of the...
  12. D

    MATLAB: expressing a double index equation as a matrix

    oh thanks a lot Grep, that REALLY helped me, now I've finished :)
  13. D

    MATLAB: expressing a double index equation as a matrix

    well, the problem is that my equation is not so simple, it is actually a pretty big fluid dynamics model for calculating the viscosity of a mixture of 10 gases, so I have an equation, lots of constant properties, and Im trying to get a 10x10 matrix :S
  14. D

    MATLAB: expressing a double index equation as a matrix

    like for example, if I have Iij=vi/vj considering that I know v for every i or j
  15. D

    MATLAB: expressing a double index equation as a matrix

    Just an urgent doubt, im new to matlab. So imagine an equation that has two indexes, and that can be expressed as a matrix, how can I do something like this in Matlab? using a for cycle?
  16. D

    ( ) Power series solution for ODE

    (URGENT) Power series solution for ODE 1. Homework Statement Supose there is an infinite series solution\sum b_{n}x^{n} for u''+4(x-(1/4))^2*u+C(x) = 0 where C(x) is a function (I get it in another problem, I'll put it in the relevant equations area), determinate the coefitients b_{0}...
  17. D

    Thermodynamics problem help

    No, I am actually trying to find the intermediate pressure for a 2 step compression so that the work needed is minimum
  18. D

    Thermodynamics problem help

    thanks a lot both of you, now, just another doubt, is H=C_P\Delta T+H_0 valid only for ideal gases? because Im working out another problem now, and I was planning to use the equation I got in this problem, but now it is not an ideal gas, it is air at about 25atm, is the equation valid?
  19. D

    Thermodynamics problem help

    1. Homework Statement A unit mass of an ideal gas at temperature T undergoes a reversible isothermal process from pressure P 1 to pressure P 2 while loosing heat to the surroundings at temperature T in the amount of q. If the gas constant of the gas is R, the entropy change of the gas ∆s...
  20. D

    How to not mistakes with long calculations

    LOL I know, but I will make an effort not to forget my math, I love math too much to just forget everything
  21. D

    Help with thermodynamics problem

    I think I'm getting it, I would thank you if you could recommend me some reading about this
  22. D

    Help with thermodynamics problem

    yeah, well, what i am interested in , is in finding how can I get that equation listed above, I had thought in deriving the equation for the sum of work in each phase, and finding the minimum value, however i cant set the whole thing to get that equation. Can I consider the air as an ideal gas...
  23. D

    Help with thermodynamics problem

    cmon, help me, please, how do you obtain that equation?
  24. D

    Help with thermodynamics problem

    1. Homework Statement Hi I would like you guys to help me with this problem Air is to be compressed steadily and isentropically from 1 atm to 25 atm by a two-stage compressor. To minimize the total compression work, the intermediate pressure between the two stages must be (a) 3 atm (b) 5 atm...
  25. D

    I need help with implicit derivatives

    why dont you just check another book?
  26. D

    Math Should I switch to Mathematics?

    I know it is useful for me, at some level, but since I share the class with pure chemistry and biology students, there are many things on the program that are not very useful for a chemical engineer, reactions that are only useful in the lab, for example there are lots of methods for producing...
  27. D

    Math Should I switch to Mathematics?

    I'm studying the second year of a chemical engineering degree. I have always loved mathematics, and Im pretty good at them, and since the beginning I am not satisfied with the engineering approach to mathematics, I would like to learn some more complicated math, but I'm not quite sure if I...
  28. D

    How to not mistakes with long calculations

    when its too long, it's okay to use a computer, however, dont become lazy, because probably you will need to know how to do it without a computer, for example, ive got a friend that is studying physics, and I am studying engineering, he would often talk about how great his math classes are, with...
  29. D

    Can Hydrogen be made from air and water?

    well, I already got a warning for answering just like that, so why dont you calculate it yourself? just look for an enthalpy table and use Hess's Law, draw some lewis's structures to know which bonds are broken and which are formed
  30. D

    Can Hydrogen be made from air and water?

    also water is very stable because of hydrogen bonds , if you want to produce Hydrogen gas just add an inorganic acid to some metal, like HCl and Al for instance, there are many other ways, like electrolysis on water
Top